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Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2019	Feb. 28, 2020	Jun. 28, 2019
Document And Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-34899
Entity Registrant Name	Pulse Biosciences, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-5696597
Entity Address, Address Line One	3957 Point Eden Way
Entity Address, City or Town	Hayward
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94545
City Area Code	510
Local Phone Number	906-4600
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	PLSE
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Public Float			$ 154,277,812
Entity Common Stock, Shares Outstanding		20,825,469
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0001625101
Amendment Flag	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE: Portions of the registrant’s definitive Proxy Statement relating to its 2020 Annual Meeting of Stockholders are incorporated by reference into Part III of this Form 10-K where indicated. The Proxy Statement will be filed with the U.S. Securities and Exchange Commission within 120 days after December 31, 2019.

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 6,899	$ 51,103
Investments	18,499	8,480
Prepaid expenses and other current assets	1,005	779
Total current assets	26,403	60,362
Property and equipment, net	2,566	2,173
Intangible assets, net	4,547	5,213
Goodwill	2,791	2,791
Right-of-use assets	5,114
Other assets	494	101
Total assets	41,915	70,640
Current liabilities:
Accounts payable	1,963	1,272
Accrued expenses	2,496	1,421
Deferred rent, current		415
Total current liabilities	4,459	3,108
Deferred rent, net of current		1,198
Lease liability	6,719
Total liabilities	11,178	4,306
Commitments and contingencies (Note 10)
Stockholders' equity:
Preferred stock, $0.001 par value; authorized – 50,000 shares; no shares issued and outstanding
Common stock, $0.001 par value; authorized – 500,000 shares; issued and outstanding – 20,825 shares and 20,593 shares at December 31, 2019 and 2018, respectively	21	21
Additional paid-in-capital	153,401	142,032
Accumulated other comprehensive income (loss)	4	(1)
Accumulated deficit	(122,689)	(75,718)
Total stockholders' equity	30,737	66,334
Total liabilities and stockholders' equity	$ 41,915	$ 70,640

Consolidated Statements Of Operations And Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements Of Operations And Comprehensive Loss [Abstract]
Revenue
Operating expenses:
General and administrative	$ 7,174	$ 5,606	$ 5,146	$ 4,401	$ 3,814	$ 5,675	$ 5,173	$ 5,383	22,327	20,045	15,503
Research and development	6,590	6,192	6,337	5,842	5,080	5,038	3,960	3,175	24,961	17,253	9,646
Amortization of intangible assets	167	166	166	167	166	166	167	166	666	665	665
Total operating expenses	13,931	11,964	11,649	10,410	9,060	10,879	9,300	8,724	47,954	37,963	25,814
Other income (expense):
Interest income	143	218	290	332	135	118	137	56	983	446	247
Other					(28)					(28)
Total other income	143	218	290	332	107	118	137	56	983	418	247
Loss from operations, before income taxes	(13,788)	(11,746)	(11,359)	(10,078)	(8,953)	(10,761)	(9,163)	(8,668)	(46,971)	(37,545)	(25,567)
Income tax benefit
Net loss	(13,788)	(11,746)	(11,359)	(10,078)	(8,953)	(10,761)	(9,163)	(8,668)	(46,971)	(37,545)	(25,567)
Other comprehensive loss:
Unrealized gain (losses) on available-for-sale securities	(4)	(14)	20	3	2	(3)	3	48	5	50	(44)
Comprehensive loss	$ (13,792)	$ (11,760)	$ (11,339)	$ (10,075)	$ (8,951)	$ (10,764)	$ (9,160)	$ (8,620)	$ (46,966)	$ (37,495)	$ (25,611)
Net loss per share:
Basic and diluted net loss per share	$ (0.66)	$ (0.57)	$ (0.55)	$ (0.49)	$ (0.51)	$ (0.64)	$ (0.54)	$ (0.51)	$ (2.26)	$ (2.20)	$ (1.73)
Weighted average shares used to compute net loss per common share - basic and diluted	20,799	20,774	20,728	20,679	17,656	16,927	16,881	16,842	20,746	17,078	14,754

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock Warrants to purchase common stock [Member]	Common Stock Rights Offering [Member]	Common Stock	Additional Paid-in Capital [Member] Warrants to purchase common stock [Member]	Additional Paid-in Capital [Member] Rights Offering [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Warrants to purchase common stock [Member]	Rights Offering [Member]	Total
Balance at Dec. 31, 2016			$ 13			$ 37,898	$ (7)	$ (12,606)			$ 25,298
Balance, shares at Dec. 31, 2016			13,315,000
Shares issued			$ 3			34,840					34,843
Shares issued, shares			2,820,000
Issuance of shares upon exercise of stock options			$ 1	$ 50		488			$ 50		489
Issuance of shares upon exercise of stock options, shares	522,000		162,000
Stock-based compensation expense						10,926					10,926
Unrealized gains (losses) on available-for-sale securities							(44)				(44)
Net loss								(25,567)			(25,567)
Balance at Dec. 31, 2017			$ 17			84,202	(51)	(38,173)			45,995
Balance, shares at Dec. 31, 2017			16,819,000
Shares issued		$ 4			$ 44,782					$ 44,786
Shares issued, shares		3,581,000
Issuance of shares upon exercise of stock options						498					498
Issuance of shares upon exercise of stock options, shares	24,000		145,000
Issuance of shares upon vesting of share-based compensation						327					327
Issuance of shares upon vesting of share-based compensation, shares			24,000
Stock-based compensation expense						12,338					12,338
Tax payments related to shares withheld for vested restricted stock units						(115)					(115)
Unrealized gains (losses) on available-for-sale securities							50				50
Net loss								(37,545)			(37,545)
Balance at Dec. 31, 2018			$ 21			142,032	(1)	(75,718)			$ 66,334
Balance, shares at Dec. 31, 2018			20,593,000								20,593,000
Issuance of shares upon exercise of stock options						272					$ 272
Issuance of shares upon exercise of stock options, shares	37,000		99,000						45,638		98,928
Issuance of shares under employee stock purchase plan						423					$ 423
Issuance of shares under employee stock purchase plan, shares			38,000
Issuance of shares upon vesting of restriced stock units
Issuance of shares upon vesting of restriced stock units, shares			58,000
Stock-based compensation expense						11,287					11,287
Tax payments related to shares withheld for vested restricted stock units						(613)					(613)
Unrealized gains (losses) on available-for-sale securities							5				5
Net loss								(46,971)			(46,971)
Balance at Dec. 31, 2019			$ 21			$ 153,401	$ 4	$ (122,689)			$ 30,737
Balance, shares at Dec. 31, 2019			20,825,000								20,825,000

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (46,971)	$ (37,545)	$ (25,567)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	494	645	336
Amortization of intangible assets	666	665	665
Loss on disposal of fixed assets		28
Stock-based compensation	11,287	12,338	10,926
Net premium amortization on investments	(521)	(140)	26
Landlord incentive for tenant improvements			2,119
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(226)	(367)	(144)
Accounts payable	646	490	517
Accrued expenses	841	387	245
Right-of-use assets	68
Other assets	(393)		(101)
Lease liabilities	(76)
Other current and non-current liabilities		(397)	(109)
Net cash used in operating activities	(34,185)	(23,896)	(11,087)
Cash flows from investing activities:
Purchases of property and equipment	(608)	(276)	(2,551)
Purchases of investments	(77,993)	(40,297)	(43,595)
Maturities of investments	68,500	41,815	23,148
Sales of investments		24,875
Net cash provided by (used in) investing activities	(10,101)	26,117	(22,998)
Cash flows from financing activities:
Proceeds from exercises of stock options and warrants	272	498	539
Proceeds from issuance of common stock from private placements, net of issuance costs of $199			34,843
Proceeds from issuance of common stock under employee stock purchase plan	423	327
Proceeds from issuance of common stock from rights offering, net of issuance costs of $213		44,786
Tax payments related to shares withheld for vested restricted stock units	(613)	(115)
Net cash provided by financing activities	82	45,496	35,382
Net increase (decrease) in cash and cash equivalents	(44,204)	47,717	1,297
Cash and cash equivalents at beginning of period	51,103	3,386	2,089
Cash and cash equivalents at end of period	6,899	51,103	3,386
Supplemental disclosure of noncash investing and financing activities:
Equipment purchases included in accounts payable and accrued expenses	$ 279	$ 33	$ 38

Summary Of Significant Accounting Policies

12 Months Ended

Dec. 31, 2019

Summary Of Significant Accounting Policies [Abstract]

Summary Of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Principles of Consolidation

The accompanying consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) and pursuant to the rules and regulations of the United States Securities Exchange Commission (the SEC). The consolidated financial statements include the financial statements of the Company and its wholly-owned subsidiaries and intercompany balances and transactions have been eliminated in consolidation.

Going concern

As of December 31, 2019, the Company had an accumulated deficit of $122.7 million, cash outflows from operations of $34.2 million, and cash, cash equivalents and investments of $25.4 million and anticipates that it will continue to incur significant operating losses for the next several years. Until such time as the Company can generate substantial product revenue and achieve profitability, the Company will need to raise additional capital. The Company plans to raise additional capital to fund its operations for at least the next twelve months from the date of issuance of the accompanying consolidated financial statements, including via a proposed rights offering that seeks to raise net proceeds of approximately $30 million, assuming such rights offering is fully subscribed. There is no assurance that the rights offering will be successful, or that additional financing will be available when needed or that management of the Company will be able to obtain financing on terms acceptable to the Company. Accordingly, the Company’s management cannot conclude that such plans will be effectively implemented within twelve months from the date of issuance of the accompanying consolidated financial statements.

These factors, combined with the Company’s forecast of cash required to fund operations for a period of at least twelve months from the date of issuance of the accompanying consolidated financial statements, raise substantial doubt about the Company’s ability to continue as a going concern.

The accompanying consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires the Company to make estimates that affect the amounts reported in the financial statements and accompanying notes to the financial statements. Estimates include, but are not limited to, the valuation of investments, clinical trial accruals, the valuation and recognition of stock-based compensation and useful lives assigned to long-lived assets. Actual amounts could differ from these estimates.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents and investments. The Company places its cash equivalents and investments with high credit quality financial institutions and, by policy, limits the amounts invested with any one financial institution or issuer. Deposits held with banks may exceed the amount of insurance provided on such deposits. The Company has not experienced any losses since inception.

Fair Value of Financial Instruments

The Company believes the carrying amounts of its financial instruments, including cash equivalents, prepaid expenses and other current assets, accounts payable and accrued expenses, approximate fair value due to the short-term nature of such instruments.

Cash, Cash Equivalents and Investments

The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. The Company has designated all investments as available-for-sale and therefore, such investments are reported at fair value, with unrealized gains and losses recognized in accumulated other comprehensive income (loss) (AOCI) in stockholders’ equity. The cost of marketable securities is adjusted for the amortization of premiums and discounts to expected maturity. Premium and discount amortization is included in other income, net. Realized gains and losses, as well as interest income, on available-for-sale securities are also included in other income, net. The Company includes all of its available-for-sale securities in current assets.

All of the Company’s investments are subject to annual impairment review. The Company recognizes an impairment loss when a decline in the fair value of its marketable investments below the cost basis is judged to be other-than-temporary. Factors considered in determining whether a loss is temporary include the length of time and extent to which the marketable investments fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, extent of the loss related to credit of the issuer, the expected cash flows from the security, the Company’s intent to sell the security and whether or not the Company will be required to sell the security before the recovery of its amortized cost. No impairment losses were incurred during the periods presented.

Property and Equipment

Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or estimated useful life. Equipment is recorded at cost and depreciated using the straight-line method over their estimated useful lives, ranging from three to five years.

Intangible Assets

The Company’s intangible assets consist of acquired patents and licenses, which are amortized over their estimated useful lives of twelve years.

Long-Lived Assets

The Company reviews long-lived assets, consisting of property and equipment and intangible assets, for impairment during each fiscal year or when events or changes in circumstances indicate the carrying value of these assets may exceed their current fair values. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the estimated undiscounted future cash flows expected to be generated by the asset. No impairment losses were incurred during the periods presented.

Goodwill

The Company records goodwill when the consideration paid in a business acquisition exceeds the fair value of the net tangible assets and the identified intangible assets acquired. The Company reviews goodwill for impairment at the reporting unit level at least annually or whenever changes in circumstances indicate that the carrying value of the goodwill may not be recoverable. To date, there has been no impairment of goodwill.

Stock-Based Compensation

The Company recognizes the cost of stock-based compensation in the financial statements based upon fair value. The fair value of stock options is determined as of the grant date using the Black-Scholes option pricing model. The fair value of restricted stock and restricted stock unit (RSU) awards is determined based on the number of units granted and the closing price of the Company’s common stock on the grant date. The fair value of each purchase under the employee stock purchase plan (ESPP) is estimated at the beginning of the offering period using the Black-Scholes option pricing model. The Company’s determination of the fair value of equity-settled awards is impacted by the price of the Company's common stock as well as changes in assumptions regarding a number of complex and subjective variables. These variables include, but are not limited to, the expected term that awards will remain outstanding, expected common stock price volatility over the term of the awards, risk-free interest rates and expected dividends. The fair value of an award is recognized over the period during which service is required to be performed in exchange for the award, the requisite service period (usually the vesting period) on a straight-line basis.

Equity instruments issued to non-employees are recorded at their fair value on the grant date and are subject to periodic adjustments as the underlying equity instruments vest. The fair value of these equity instruments are expensed over the service period.

Estimates of the fair value of equity-settled awards as of the grant date using valuation models, such as the Black-Scholes option pricing model, are affected by assumptions regarding a number of complex variables. Changes in the assumptions can materially affect the fair value of the award and the stock-based compensation expense recognized. These inputs are subjective and generally require significant analysis and judgment to develop. The Company determines the volatility factor based on the historical volatilities of comparable public companies in similar industries. The risk-free interest rate is based on the yield available on U.S. Treasury zero-coupon issues similar in duration to the expected term of the equity-settled award. For all stock options granted to date, the Company used the simplified method to calculate the expected term, which is the average of the contractual term and vesting period. Prior to the Company’s initial public offering, the fair value of common stock was determined by reference to either recent or anticipated cash transactions involving the sale of the Company’s common stock.

The Company recognizes the fair value of stock-based compensation costs in general and administrative costs and in research and development costs, as appropriate, in the Company’s consolidated statements of operations.

Research and Development Costs

Research and development costs consist primarily of compensation costs, fees paid to consultants and outside service providers and organizations (including university research institutes), costs associated with clinical trials, development prototypes and other expenses relating to the acquisition, design, development and testing of the Company’s product candidates, and certain facilities related costs. Research and development costs incurred by the Company are expensed as incurred, unless the achievement of milestones, the completion of contracted work, or other information indicates that a different expensing schedule is more appropriate.

Patent Costs

The Company is the owner of numerous domestic and foreign patents. Due to the significant uncertainty associated with the successful development of one or more commercially viable products based on the Company’s research efforts and any related patent applications, patent costs not related to acquired patents, including patent-related legal fees, filing fees and other costs, including internally generated costs, are expensed as incurred. During the years ended December 31, 2019, 2018 and 2017, patent costs totaled $0.6 million, $0.6 million and $0.8 million, respectively. Patent costs are included in general and administrative costs in the consolidated statements of operations and comprehensive loss.

Income Taxes

The Company accounts for income taxes under an asset and liability approach for financial accounting and reporting for income taxes. Accordingly, the Company recognizes deferred tax assets and liabilities for the expected impact of differences between the financial statements and the tax basis of assets and liabilities.

The Company records a valuation allowance to reduce its deferred tax assets to the amount that is more-likely-than-not to be realized. In the event the Company determines that it would be able to realize its deferred tax assets in the future in excess of its recorded amount, an adjustment to the deferred tax assets would be credited to operations in the period such determination was made. Likewise, should the Company determine that it would not be able to realize all or part of its deferred tax assets in the future, an adjustment to the deferred tax assets would be charged to operations in the period such determination was made.

The Company is subject to U.S. federal income taxes and income taxes in the State of California. As the Company’s net operating losses have yet to be utilized, previous tax years remain open to examination by federal authorities and other jurisdictions in which the Company currently operates or has operated in the past. The Company is not currently under examination by any tax authority.

The Company accounts for uncertainties in income tax law under a comprehensive model for the financial statement recognition, measurement, presentation and disclosure of uncertain tax positions taken or expected to be taken in income tax returns as prescribed by U.S. GAAP. The tax effects of a position are recognized only if it is more-likely-than-not to be sustained by the taxing authority as of the reporting date. If the tax position is not considered more-likely-than-not to be sustained, then no benefits of the position are recognized. At December 31, 2019 and 2018, the Company had not recorded any liability for uncertain tax positions. The Company includes interest and penalties related to uncertain tax positions as a component of income tax expense.

Comprehensive Loss

Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company displays comprehensive loss and its components as part of the consolidated statements of operations and comprehensive loss.

Net Loss per Share

The Company calculates basic net loss per share by dividing net loss by the weighted average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by giving effect to all potential dilutive common stock equivalents outstanding during the period. For purposes of this calculation, options to purchase common stock and common stock warrants are considered common stock equivalents. Potential common shares that have an anti-dilutive effect (i.e., those that increase income per share or decrease loss per share) are excluded from the calculation of diluted net loss per share.

The following outstanding stock options, warrants and RSUs to purchase common stock were excluded from the computation of diluted net loss per share for the periods presented because including them would have had an anti-dilutive effect:



	Year Ended December 31,
	2019		2018		2017
Common stock warrants		167,847		213,485		249,709
Common stock options		3,749,186		2,956,687		2,598,659
Restricted stock units		222,606		222,606		229,774
Total		4,139,639		3,392,778		3,078,142

Segment and Geographical Information

The Company operates and manages its business as one reportable and operating segment. The Company’s Chief Executive Officer, who is the chief operating decision maker, reviews financial information on an aggregate basis for purposes of allocating resources and evaluating financial performance. All of the Company’s assets are based in the United States (U.S.).

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers, requiring an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. This updated standard became effective for the Company in the first quarter of fiscal year 2018. Since the Company has not recognized or generated revenue to date, the adoption of this pronouncement did not have any impact to its financial statements.

In February 2016, the FASB issued ASU No. 2016-02, Leases, amended Accounting Standard Codification (ASC) 842, Leases. The new standard requires lessees to record a right-of-use asset and a corresponding lease liability on the balance sheet (with the exception of short-term leases). The Company adopted ASC 842 on January 1, 2019, using the modified retrospective transition method per ASU No. 2018-11 issued on July 2018 wherein entities were allowed to initially apply the new lease standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Accordingly, all periods prior to January 1, 2019 were presented in accordance with ASC 840, Leases, and no retrospective adjustments were made to the comparative periods presented. The adoption of ASC 842 resulted in an increase to total assets and liabilities due to the recording of operating lease right-of-use assets (ROU) presented within other assets and operating lease liabilities of approximately $0.1 million as of January 1, 2019.

In June 2018, the FASB issued ASU 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Non-employee Share-Based Payment Accounting, which expands the scope of Topic 718, Compensation—Stock Compensation to include share-based payments issued to non-employees for goods or services. Consequently, the accounting for share-based payments to non-employees and employees will be substantially aligned. The Company adopted ASU 2018-07 in the first quarter of 2019, and the adoption had no significant impact to its financial statements.

In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which eliminates certain exceptions related to the general principles in ASC 740 and makes amendments to other areas with the intention of simplifying various aspects related to accounting for income taxes. The new standard is effective for fiscal years beginning after December 15, 2020, including interim periods therein; with early adoption permitted. The Company is currently evaluating the impact that the standard will have on its financial statements and related disclosures; and does not expect the adoption to have a material impact on the Company’s financial statements.

Investments And Fair Value Of Financial Instruments

12 Months Ended

Dec. 31, 2019

Investments And Fair Value Of Financial Instruments [Abstract]

Investments And Fair Value Of Financial Instruments

3. Investments and Fair Value of Financial Instruments

Investments

The Company’s investments have been classified and accounted for as available-for-sale. The Company’s investments consisted of the following (in thousands):



		December 31, 2019
		Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	18,495	$	4	$	—	$	18,499
Total assets measured at fair value	$	18,495	$	4	$	—	$	18,499



		December 31, 2018
		Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	8,481	$	—	$	(1)	$	8,480
Total assets measured at fair value	$	8,481	$	—	$	(1)	$	8,480

The contractual maturities of the Company’s investments were as follows (in thousands):



	December 31,
Investments	2019		2018
Due in one year	$	18,499	$	8,480
Due in one to two years		—		—
Total	$	18,499	$	8,480

Fair Value of Financial Instruments

The Company determines the fair value of its financial instruments based on a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels:

Level 1 - Observable inputs such as quoted prices in active markets for an identical asset or liability that the Company has the ability to access as of the measurement date. Financial assets and liabilities utilizing Level 1 inputs include money market funds.

Level 2 - Inputs, other than quoted prices included within Level 1, which are directly observable for the asset or liability or indirectly observable through corroboration with observable market data. Financial assets and liabilities utilizing Level 2 inputs include commercial paper, corporate bonds and asset-backed securities.

Level 3 - Unobservable inputs in which there is little or no market data for the asset or liability which requires the reporting entity to develop its own assumptions. The Company did not classify any of its investments within Level 3 of the fair value hierarchy.

The following table sets forth the fair value of the Company’s financial assets measured on a recurring basis (in thousands):



			December 31, 2019
Assets	Classification		Level 1		Level 2		Level 3		Total
Money market funds	Cash and cash equivalents	$	6,429	$	—	$	—	$	6,429
U.S. Treasury securities	Investments		—		18,499		—		18,499
Total assets measured at fair value		$	6,429	$	18,499	$	—	$	24,928



			December 31, 2018
Assets	Classification		Level 1		Level 2		Level 3		Total
Money market funds	Cash and cash equivalents	$	50,703	$	—	$	—	$	50,703
U.S. Treasury securities	Investments		—		8,480		—		8,480
Total assets measured at fair value		$	50,703	$	8,480	$	—	$	59,183

During year ended December 31, 2019 and 2018, the Company did not record impairment charges related to its marketable investments. During the years ended December 31, 2019 and 2018, the Company did not have any transfers between Level 1, Level 2 or Level 3 of the fair value hierarchy. Additionally, the Company did not have any financial assets and liabilities measured at fair value on a non-recurring basis as of December 31, 2019 or 2018.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Balance Sheet Components

12 Months Ended

Dec. 31, 2019

Balance Sheet Components [Abstract]

Balance Sheet Components

4. Balance Sheet Components

Property and Equipment, net

Property and equipment, net consisted of the following (in thousands):



	December 31,
	2019		2018
Leasehold improvements	$	2,248	$	2,248
Laboratory equipment		677		518
Furniture, fixtures and equipment		466		248
Software		118		118
Construction in progress		543		33
		4,052		3,165
Less: Accumulated depreciation and amortization		(1,486)		(992)
	$	2,566	$	2,173

The lease for Company’s current premises in Hayward, California began in July 2017, per terms of the lease, the landlord provided $2.1 million in tenant improvement allowance which was capitalized.

Depreciation and amortization expense for the years ended December 31, 2019, 2018, and 2017 was $0.5 million, $0.6 million, and $0.3 million, respectively.

Intangible Assets, net

Intangible assets primarily consist of a license to utilize certain patents, know-how and technology relating to the Company’s NPS for biomedical applications acquired from Old Dominion University Research Foundation (ODURF), Eastern Virginia Medical School (EVMS), and the University of Southern California. In addition, the Company entered into a Sponsored Research Agreement with Old Dominion University’s Frank Reidy Research Center for Bioelectrics, a leading research organization in the field, which includes certain intellectual property rights arising from the research. The Company is amortizing the intangible assets over an estimated useful life of 12 years.

Intangible assets, net consisted of the following (in thousands):



	December 31,
	2019		2018
Acquired patents and licenses	$	7,985	$	7,985
Less: Accumulated amortization		(3,438)		(2,772)
	$	4,547	$	5,213

A schedule of the amortization of intangible assets is as follows (in thousands):



Years ending December 31:
2020	$	665
2021		665
2022		665
2023		665
2024		665
Thereafter		1,222
	$	4,547

Accrued Expenses

Accrued expenses consisted of the following (in thousands):



	December 31,
	2019		2018
Compensation expense	$	1,699	$	938
Accrued clinical		262		156
Professional fees		51		274
Property and equipment		234		—
Other		250		53
	$	2,496	$	1,421

The compensation expense includes approximately $0.3 million relating to the departure of an executive officer.

Stockholders' Equity And Stock-Based Compensation

12 Months Ended

Dec. 31, 2019

Stockholders' Equity And Stock-Based Compensation [Abstract]

Stockholders' Equity And Stock-Based Compensation

6. Stockholders’ Equity and Stock-Based Compensation

Preferred Stock

The Company has authorized a total of 50,000,000 shares of preferred stock, par value $0.001 per share, none of which were outstanding at December 31, 2019 and 2018. The Company’s Board of Directors (the Board) has the authority to issue preferred stock and to determine the rights, preferences, privileges, and restrictions, including voting rights, without any further vote or action by the Company’s stockholders.

Common Stock

The Company has authorized a total of 500,000,000 shares of common stock, par value $0.001 per share.

Private Placements

During February 2017, the Company entered into a securities purchase agreement, pursuant to which the Company, in a private placement, issued and sold an aggregate of 819,673 shares of the Company’s common stock, par value $0.001 per share, at a price per share of $6.10, for net proceeds of approximately $5.0 million.

During September 2017, the Company entered into a securities purchase agreement with an existing investor, pursuant to which the Company, in a private placement, issued and sold an aggregate of 2,000,000 shares of the Company’s common stock, par value $0.001 per share, at a price per share of $15.02, for net proceeds of approximately $29.9 million.

Rights Offering

On October 25, 2018, the Company commenced a rights offering pursuant to which stockholders of record as of November 19, 2018, were issued, at no charge, one subscription right for each share of common stock then outstanding. Each right entitled the holder to purchase 0.19860755 share of the Company’s common stock for $12.57 per share (the “Rights Offering”).

Stockholders who exercised their rights in full were also permitted an over-subscription right to purchase additional shares of common stock that remained unsubscribed at the expiration of the Rights Offering, subject to the availability of shares and a pro rata allocation of shares among persons exercising the oversubscription right.

Upon the closing of the Rights Offering on December 6, 2018, the Rights Offering was oversubscribed. A total of 3,581,148 shares of the Company’s common stock were issued and sold in the Rights Offering for net proceeds of approximately $44.8 million. Robert W. Duggan, the Company’s Chairman of the Board of Directors and the beneficial owner of approximately 35% of the Company’s outstanding common stock prior to the Rights Offering, participated in the Rights Offering and purchased an aggregate of 3,146,226 shares for an additional investment of approximately $39.5 million.

Common Stock Warrants

In connection with a private placement offering of the Company’s shares of common stock, par value $0.001 per share in 2014, the Company issued warrants as compensation to the placement agent to purchase a total of 299,625 shares of its common stock at a price of $2.67 per share (Private Placement Warrants). The Private Placement Warrants are exercisable for a period of seven years. As of December 31, 2019, there were a total of 46,238 of Private Placement Warrants outstanding.

In connection with the closing of the Company’s initial public offering in 2016, the Company issued warrants as compensation to its underwriters, as representatives of the underwriters of its initial public offering to purchase a total of 574,985 shares of its common stock at a price of $5.00 per share (IPO Warrants). The IPO Warrants are exercisable for a period of five years. As of December 31, 2019, there were a total of 121,609 of the IPO Warrants outstanding.

A summary of total warrants activity for the year ended December 31, 2019 is presented below:



				Weighted
				Average
		Weighted		Remaining
	Number of	Average		Contractual
	Shares	Exercise Price		Life (in Years)
Warrants outstanding at December 31, 2018	213,485	$	4.00	2.37
Issued	—
Exercised	(45,638)	$	2.67
Expired/terminated	—
Warrants outstanding and exercisable at December 31, 2019	167,847	$	4.36	1.28

During the year ended December 31, 2019, warrants to purchase 45,638 shares of common stock were net exercised, resulting in the issuance of approximately 37,320 shares of common stock.

The intrinsic value of exercisable in-the-money stock warrants was approximately $1.5 million as of December 31, 2019.

Equity Plans

2017 Equity Incentive Plan and 2017 Inducement Equity Incentive Plan

The Board previously adopted, and the Company’s stockholders approved, the Company’s 2017 Equity Incentive Plan (the 2017 Plan).

The 2017 Plan has a 10-year term, and provides for the grant of stock options, stock appreciation rights, restricted stock, RSUs, performance units, and performance shares to employees, directors and consultants of the Company and any parent or subsidiary of the Company, as the Compensation Committee of the Board may determine. The 2017 Plan is administered by the Board’s Compensation Committee.

Subject to an annual evergreen increase and adjustment in the case of certain capitalization events, the Company initially reserved 1,500,000 shares of the Company’s common stock for issuance pursuant to awards under the 2017 Plan. In addition, shares remaining available under the Company’s 2015 Equity Incentive Plan, as amended (the “2015 Plan”), and shares reserved but not issued pursuant to outstanding equity awards that expire or terminate without being exercised or that are forfeited or repurchased by the Company will be added to the shares of common stock available for issuance under the 2017 Plan.

Effective January 1, 2019, the number of shares of common stock available under the 2017 Plan increased by 823,716 shares pursuant to the evergreen provision of the 2017 Plan. Under the evergreen provision of the 2017 Plan, the share increase is determined based on the least of (i) 1,200,000 shares, (ii) 4% of the Company’s common stock outstanding at December 31 of the immediately preceding year, or (iii) such number of shares as determined by the Board. As of December 31, 2019, 998,288 shares of common stock remained available for issuance under the 2017 Plan.

During November 2017, the Board of the Company adopted the 2017 Inducement Equity Incentive Plan (the “Inducement Plan”) and reserved 1,000,000 shares of the Company’s common stock for issuance pursuant to equity awards granted under the Inducement Plan. The Inducement Plan was adopted without stockholder approval.

The Inducement Plan has a 10-year term, and provides for the grant of equity-based awards, including non-statutory stock options, RSUs, restricted stock, stock appreciation rights, performance shares and performance units, and its terms are substantially similar to the 2017 Plan, including with respect to treatment of equity awards in the event of a “merger” or “change in control” as defined under the Inducement Plan. Options issued under the Inducement Plan may have a term up to ten years and have variable vesting provisions. New hire grants generally vest 25% upon the first anniversary of the grant and 1/48th monthly thereafter, over the subsequent 36 months. Equity-based awards issued under the Inducement Plan are only issuable to individuals not previously engaged as employees or non-employee directors of the Company prior to the Inducement Plan’s adoption date. As of December 31, 2019, 78,950 shares of common stock were available for issuance under the Inducement Plan.

2017 Employee Stock Purchase Plan

The Board previously adopted and the stockholders approved the Company’s 2017 Employee Stock Purchase Plan (the 2017 ESPP).

The 2017 ESPP is a broad-based plan that provides employees of the Company and its designated affiliates with the opportunity to become stockholders through periodic payroll deductions that are applied towards the purchase of Company common shares at a discount from the then-current market price. Subject to adjustment in the case of certain capitalization events, a total of 250,000 common shares of the Company were available for purchase at adoption of the 2017 ESPP. In January 2019, the Board determined not to increase the number of shares of common stock available under the 2017 ESPP pursuant to the evergreen provision of the 2017 ESPP. Pursuant to the 2017 ESPP, the annual share increase pursuant to the evergreen provision is determined based on the least of (i) 450,000 shares, (ii) 1.5% of the Company’s common stock outstanding at December 31 of the immediately preceding year, or (iii) such number of shares as determined by the Board. During the year ended December 31, 2019 and 2018, the Company issued 38,279 and 23,869 shares of common stock under the 2017 ESPP, respectively. As of December 31, 2019, 440,195 shares of common stock remained available for issuance under the 2017 ESPP.

A summary of stock option activity under the 2015 Plan, 2017 Plan and Inducement Plan for the year ended

December 31, 2019 is presented below:



				Weighted
		Weighted		Average
		Average		Remaining
	Number of	Exercise		Contractual
	Shares	Price		Life (in Years)
Balances - December 31, 2018	2,956,687	$	17.04	7.6
Options granted	1,162,616		13.60
Options exercised	(98,928)		2.75
Options canceled	(99,669)		15.66
Options expired	(171,520)		21.61
Balances - December 31, 2019	3,749,186	$	16.18	7.9
Stock options exercisable at December 31, 2019	2,110,219	$	16.33	6.5

The table above excludes 42,500 performance stock options granted during the year ended December 31, 2019 for which the performance criteria had not been established as of December 31, 2019.

The intrinsic value of stock options exercised during the year ended December 31, 2019, 2018 and 2017 was $1.0 million, $1.8 million, and $3.8 million, respectively.

The fair value of employee stock options was estimated using the Black-Scholes option-pricing model utilizing the following assumptions:



	Year Ended December 31,
	2019		2018		2017
Expected term in years		0.4 - 6.1		5.3 - 6.1		0.4 - 6.1
Expected volatility		70%		70%		70% - 90%
Risk-free interest rate		1.4 - 2.6%		2.6 - 3.0%		1.0% - 2.2%
Dividend yield		—		—		—

The fair value of the stock options granted to employees and directors during the years ended December 31, 2019, 2018 and 2017 was $8.4 million, $6.4 million, and $26.8 million, respectively.

The fair value of ESPP was estimated using the Black-Scholes option-pricing model utilizing the following assumptions:


	Year Ended December 31,
	2019		2018		2017
Expected term in years		0.5 - 1.0		0.5 - 1.0		0.5 - 1.3
Expected volatility		70%		70%		95%
Risk-free interest rate		1.7% - 2.6%		1.9% - 2.5%		1.1% - 1.2%
Dividend yield		—		—		—

Total stock-based compensation expense was as follows (in thousands):


	Year Ended December 31,
	2019		2018		2017
General and administrative	$	7,466	$	9,004	$	9,136
Research and development		3,821		3,334		1,790
Total stock-based compensation expense	$	11,287	$	12,338	$	10,926

The fair value of RSU awards is determined based on the number of units granted and the closing price of the Company’s common stock as of the grant date. The estimated fair value of RSUs is recognized on a straight-line basis over the requisite service period. During 2017, the Company granted 160,974 RSUs all of which vested pursuant to which no shares were issued, during June 2018. Additional paid in capital was reduced by $0.1 million for tax payments related to shares withheld in connection with the vesting of the RSUs. The stock-based compensation expense related to these RSUs was approximately $2.1 million and $2.9 million during the years ended December 31, 2018 and 2017, respectively. As of December 31, 2019, there was no unrecognized compensation expense related to these RSUs.

During the year ended December 31, 2017, the Company granted 68,800 RSUs to certain employees, of which 50% vested on June 1, 2019 with the remaining 50% vesting on June 1, 2021. In the event of a change in control, these RSUs vest 100%. The stock-based compensation expense recorded in 2018 and 2017 related to these RSUs was approximately $0.4 million and $0.1 million, respectively. As of December 31, 2018, there was $0.9 million of unrecognized compensation expense related to these RSUs.

During November 2017, the resignations of certain Board members resulted in full vesting of their outstanding equity awards. Accordingly, the Company recorded an additional $1.2 million of stock-based compensation expense for the year ended December 31, 2017.

At December 31, 2019, there was $14.2 million of unrecognized compensation cost related to unvested stock-based compensation arrangements, which is expected to be recognized over a weighted average period of 2.8 years.

Income Taxes

12 Months Ended

Dec. 31, 2019

Income Taxes [Abstract]

Income Taxes

8. Income Taxes

The pre-tax book loss for the Company was approximately $47 million, $37.5 million and $25.8 million for the years ended December 31, 2019, 2018 and 2017, respectively; these losses were incurred in the U.S., the Company has no foreign subsidiaries. The income tax provision was $0 for the years ended December 31, 2019, 2018 and 2017.

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets at December 31, 2019 and 2018 are summarized below (in thousands):



	December 31,
	2019		2018
Temporary differences	$	119	$	111
Credits		4,409		5,330
Stock compensation		5,473		2,630
Lease liability under ASC 842		1,411		—
Net operating loss carryforwards		20,755		15,365
Total deferred tax assets before valuation allowance		32,167		23,436
Valuation allowance		(30,369)		(22,696)
Total deferred tax assets after valuation allowance		1,798		740
Technology deferred tax liability		(434)		(740)
Right of use assets under ASC 842		(1,364)		—
Net deferred tax assets	$	—	$	—

In assessing the potential realization of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the Company attaining future taxable income during the periods in which those temporary differences become deductible. At December 31, 2019 and 2018, management was unable to determine that it was more likely than not that the Company’s deferred tax assets will be realized, and has therefore recorded an appropriate valuation allowance against deferred tax assets at such dates.

The Company’s effective tax rate is different from the federal statutory tax rate of 21% due primarily to net losses that receive no tax benefit as a result of a valuation allowance recorded for such losses.

Presented below is the reconciliation of the difference between the tax rate computed by applying the U.S. federal statutory tax rate and the effective tax rate for the years ended December 31, 2019, 2018 and 2017:



	Year Ended December 31,
	2019		2018		2017
U.S. federal statutory tax rate	(21.0)	%	(21.0)	%	(35.0)	%
Valuation allowance	18.0		28.0		23.0
Tax reform	—		(2.0)		18.0
Credits	(2.0)		2.0		1.0
State tax benefit and other	5.0		(7.0)		(7.0)
Effective tax rate	—	%	—	%	—	%

At December 31, 2019, the Company had federal and California state net operating loss carryforwards of approximately $87.8 million and $25.8 million, respectively, these will begin to expire in 2034. Of the total federal net operating loss (NOL) carryforward of $87.8 million, approximately $62.2 million was generated after tax year 2017 and has an indefinite carryover period; the utilizations of theses NOLs will be limited to 80% of the taxable income in the years in which these NOLs are utilized. Utilization of some of the federal and California net operating loss carry-forwards are subject to annual limitations due to the ‘change in ownership’ provisions of the Internal Revenue Code of 1986 and similar provisions.

At December 31, 2019, the Company had approximately $2.4 million and $2.0 million of federal and California research and development (R&D) credits, respectively. The federal R&D credits begin to expire after 2035 and the California R&D credits have an indefinite carryforward period.

These net operating loss carryforward and R&D credits amounts have full valuation allowances against them due to the remoteness of their expected utilization.

The Company’s activity related to unrecognized tax benefits are summarized below (in thousands):


	December 31,
	2019		2018		2017
Balance at the beginning of the year	$	877	$	512	$	213
Gross increases - tax positions in prior periods		—		—		37
Gross decreases - tax positions in prior periods		—		—		—
Gross increases - tax position in current period		593		365		262
Settlements		—		—		—
Lapses in statutes of limitations		—		—		—
Balance at the end of the year	$	1,470	$	877	$	512

Although it is reasonably possible that certain unrecognized tax benefits may increase or decrease within the next twelve months due to tax examination changes, settlement activities, expirations of statute of limitations, or the impact on recognition and measurement considerations related to the results of published tax cases or other similar activities, the Company does not anticipate any significant changes to unrecognized tax benefits over the next 12 months. During the years ended December 31, 2019, 2018 and 2017, no interest or penalties were required to be recognized related to unrecognized tax benefits. Although the Company is not under examination, the tax years for 2014 and forward are subject to examination by U.S. tax authorities.

Commitments And Contingencies

12 Months Ended

Dec. 31, 2019

Commitments And Contingencies [Abstract]

Commitments And Contingencies

10. Commitments and Contingencies

Operating Leases

During January 2017, the Company entered into a five year for approximately 15,700 square feet for its corporate headquarters located in Hayward, California. The lease commenced during July 2017.

During May 2019, the Company entered into Lease Amendment 1 (the Amendment) in relation to the existing lease (Existing Lease or Existing Premises). In executing the Amendment, the Company added the lease of new premises of approximately 13,300 square feet and 21,300 square feet, (Expansion Premises 1 and Expansion Premises 2, respectively). Additionally, the term of the Existing Lease was extended to be coterminous with Expansion Premises 1 and Expansion Premises 2, effective October 2029.

The Company evaluated the lease amendment under the provisions of ASC 842 that it adopted on January 1, 2019, and concluded that the Amendment would be accounted for as a single contract with the Existing Lease because the additional lease payments due to the Amendment was not commensurate with ROU asset granted to the Company. Though the Amendment was accounted for as a single contract, the Existing Premises, Expansion Premises 1 (occupied in November 2019) and Expansion Premises 2 (not yet occupied) are each accounted for as separate lease components. Accordingly, the Company measured and allocated consideration to each lease component as of the modification date. Upon commencement of each lease component, the Company will reassess and calculate the lease liability and ROU asset for the respective component. As a result, at the modification date, the Company remeasured its existing lease liability and recorded an additional ROU asset and lease liability of $2.0 million. The Company also recorded an additional ROU asset and lease liability of $3.0 million at the commencement of Expansion Premises 1 in November 2019. At December 31, 2019, total ROU assets and lease lability including the impact of ASC 842 adoption, was approximately $5.1 million and $6.7 million, respectively.

During the years ended December 31, 2019, 2018 and 2017, rent expense, including common area maintenance charges, was $0.5 million, $0.2 million and $0.3 million, respectively.

Information related to the Company's ROU assets and related lease liabilities were as follows (in thousands except for remaining lease term and discount rate):




Year ending December 31:
2020	$	647
2021		986
2022		1,071
2023		1,094
Thereafter		7,190
Total lease payments		10,988
Less imputed interest		(4,269)
Total lease liabilities	$	6,719

Other supplemental non-cash information:
Cash paid for operating lease liabilities	$	406
Operating lease liabilities arising from ROU assets including impact of ASC 842 adoption	$	5,114

Current operating lease liabilities		—
Non-current operating lease liabilities		6,719
Total lease liabilities	$	6,719

Weighted-average remaining lease term		9.83
Weighted-average discount rate		10%

Indemnification

The Company maintains indemnification agreements with its directors and officers that may require the Company to indemnify them against liabilities that arise by reason of their status or service as directors or officers, except as prohibited by applicable law.

From time to time, the Company may be involved in a variety of claims, lawsuits, investigations and proceedings relating to securities laws, product liability, patent infringement, contract disputes and other matters relating to various claims that arise in the normal course of our business in addition to governmental and other regulatory investigations and proceedings. In addition, third parties may, from time to time, assert claims against the Company in the form of letters and other communications. The Company currently believes that these ordinary course matters will not have a material adverse effect on our business; however, the results of litigation and claims are inherently unpredictable. Regardless of the outcome, litigation can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources and other factors.

Selected Quarterly Financial Data

12 Months Ended

Dec. 31, 2019

Selected Quarterly Financial Data [Abstract]

Selected Quarterly Financial Data

12. Selected Quarterly Financial Data (Unaudited)

The following table provides the selected quarterly financial data for the years ended December 31, 2019 and 2018 (in thousands, except per share data):


	Quarter Ended
	2019								2018
	December 31,		September 30,		June 30,		March 31,		December 31,		September 30,		June 30,		March 31,
Revenue	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Operating expenses:
General and administrative		7,174		5,606		5,146		4,401		3,814		5,675		5,173		5,383
Research and development		6,590		6,192		6,337		5,842		5,080		5,038		3,960		3,175
Amortization of intangible assets		167		166		166		167		166		166		167		166
Total operating expenses		13,931		11,964		11,649		10,410		9,060		10,879		9,300		8,724
Other income (expense):
Interest income		143		218		290		332		135		118		137		56
Other expense		—		—		—		—		(28)		—		—		—
Total other income		143		218		290		332		107		118		137		56
Loss from operations, before income taxes		(13,788)		(11,746)		(11,359)		(10,078)		(8,953)		(10,761)		(9,163)		(8,668)
Income tax benefit		—		—		—		—		—		—		—		—
Net loss		(13,788)		(11,746)		(11,359)		(10,078)		(8,953)		(10,761)		(9,163)		(8,668)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale securities, net of tax:		(4)		(14)		20		3		2		(3)		3		48
Comprehensive loss	$	(13,792)	$	(11,760)	$	(11,339)	$	(10,075)	$	(8,951)	$	(10,764)	$	(9,160)	$	(8,620)
Net loss per share
Basic and diluted net loss per share	$	(0.66)	$	(0.57)	$	(0.55)	$	(0.49)	$	(0.51)	$	(0.64)	$	(0.54)	$	(0.51)
Weighted average shares used to compute net loss per common share — basic and diluted		20,799		20,774		20,728		20,679		17,656		16,927		16,881		16,842

Summary Of Significant Accounting Policies (Policy)

12 Months Ended

Dec. 31, 2019

Summary Of Significant Accounting Policies [Abstract]

Principles Of Consolidation

Principles of Consolidation

Use Of Estimates

Use of Estimates

Concentration Of Credit Risk

Concentration of Credit Risk

Fair Value Of Financial Instruments

Fair Value of Financial Instruments

Cash, Cash Equivalents, And Investments

Cash, Cash Equivalents and Investments

Property and Equipment

Intangible Assets

The Company’s intangible assets consist of acquired patents and licenses, which are amortized over their estimated useful lives of twelve years.

Long-Lived Assets

Goodwill

Stock-Based Compensation

Research And Development Costs

Research and Development Costs

Net Loss per Share



	Year Ended December 31,
	2019		2018		2017
Common stock warrants		167,847		213,485		249,709
Common stock options		3,749,186		2,956,687		2,598,659
Restricted stock units		222,606		222,606		229,774
Total		4,139,639		3,392,778		3,078,142

Segment And Geographical Information

Segment and Geographical Information

Recently Accounting Pronouncements

Recent Accounting Pronouncements

Investments And Fair Value Of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2019

Investments And Fair Value Of Financial Instruments [Abstract]

Schedule Of Available-For-Sale Securities



		December 31, 2019
		Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	18,495	$	4	$	—	$	18,499
Total assets measured at fair value	$	18,495	$	4	$	—	$	18,499



		December 31, 2018
		Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	8,481	$	—	$	(1)	$	8,480
Total assets measured at fair value	$	8,481	$	—	$	(1)	$	8,480

Schedule Of Contractual Maturities



	December 31,
Investments	2019		2018
Due in one year	$	18,499	$	8,480
Due in one to two years		—		—
Total	$	18,499	$	8,480

Fair Value Of Financial Assets Measured On A Recurring Basis



			December 31, 2019
Assets	Classification		Level 1		Level 2		Level 3		Total
Money market funds	Cash and cash equivalents	$	6,429	$	—	$	—	$	6,429
U.S. Treasury securities	Investments		—		18,499		—		18,499
Total assets measured at fair value		$	6,429	$	18,499	$	—	$	24,928



			December 31, 2018
Assets	Classification		Level 1		Level 2		Level 3		Total
Money market funds	Cash and cash equivalents	$	50,703	$	—	$	—	$	50,703
U.S. Treasury securities	Investments		—		8,480		—		8,480
Total assets measured at fair value		$	50,703	$	8,480	$	—	$	59,183

Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2019

Balance Sheet Components [Abstract]

Schedule Of Property And Equipment, Net



	December 31,
	2019		2018
Leasehold improvements	$	2,248	$	2,248
Laboratory equipment		677		518
Furniture, fixtures and equipment		466		248
Software		118		118
Construction in progress		543		33
		4,052		3,165
Less: Accumulated depreciation and amortization		(1,486)		(992)
	$	2,566	$	2,173

Schedule Of Intangible Assets, Net



	December 31,
	2019		2018
Acquired patents and licenses	$	7,985	$	7,985
Less: Accumulated amortization		(3,438)		(2,772)
	$	4,547	$	5,213

Schedule Of Amortization Of Intangible Assets



Years ending December 31:
2020	$	665
2021		665
2022		665
2023		665
2024		665
Thereafter		1,222
	$	4,547

Schedule Of Accrued Expenses



	December 31,
	2019		2018
Compensation expense	$	1,699	$	938
Accrued clinical		262		156
Professional fees		51		274
Property and equipment		234		—
Other		250		53
	$	2,496	$	1,421

Stockholders' Equity And Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Stockholders' Equity [Line Items]

Summary Of Stock Warrant Activity



				Weighted
				Average
		Weighted		Remaining
	Number of	Average		Contractual
	Shares	Exercise Price		Life (in Years)
Warrants outstanding at December 31, 2018	213,485	$	4.00	2.37
Issued	—
Exercised	(45,638)	$	2.67
Expired/terminated	—
Warrants outstanding and exercisable at December 31, 2019	167,847	$	4.36	1.28

Summary Of Stock Option Activity



				Weighted
		Weighted		Average
		Average		Remaining
	Number of	Exercise		Contractual
	Shares	Price		Life (in Years)
Balances - December 31, 2018	2,956,687	$	17.04	7.6
Options granted	1,162,616		13.60
Options exercised	(98,928)		2.75
Options canceled	(99,669)		15.66
Options expired	(171,520)		21.61
Balances - December 31, 2019	3,749,186	$	16.18	7.9
Stock options exercisable at December 31, 2019	2,110,219	$	16.33	6.5

Summary Of Stock-Based Compensation Expense


	Year Ended December 31,
	2019		2018		2017
General and administrative	$	7,466	$	9,004	$	9,136
Research and development		3,821		3,334		1,790
Total stock-based compensation expense	$	11,287	$	12,338	$	10,926

Options outstanding [Member]

Stockholders' Equity [Line Items]

Schedule Of Fair Value Of Employee Stock Options



	Year Ended December 31,
	2019		2018		2017
Expected term in years		0.4 - 6.1		5.3 - 6.1		0.4 - 6.1
Expected volatility		70%		70%		70% - 90%
Risk-free interest rate		1.4 - 2.6%		2.6 - 3.0%		1.0% - 2.2%
Dividend yield		—		—		—

2017 Employee Stock Purchase Plan [Member]

Stockholders' Equity [Line Items]

Schedule Of Fair Value Of Employee Stock Options


	Year Ended December 31,
	2019		2018		2017
Expected term in years		0.5 - 1.0		0.5 - 1.0		0.5 - 1.3
Expected volatility		70%		70%		95%
Risk-free interest rate		1.7% - 2.6%		1.9% - 2.5%		1.1% - 1.2%
Dividend yield		—		—		—

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Taxes [Abstract]

Components Of Deferred Tax Assets



	December 31,
	2019		2018
Temporary differences	$	119	$	111
Credits		4,409		5,330
Stock compensation		5,473		2,630
Lease liability under ASC 842		1,411		—
Net operating loss carryforwards		20,755		15,365
Total deferred tax assets before valuation allowance		32,167		23,436
Valuation allowance		(30,369)		(22,696)
Total deferred tax assets after valuation allowance		1,798		740
Technology deferred tax liability		(434)		(740)
Right of use assets under ASC 842		(1,364)		—
Net deferred tax assets	$	—	$	—

Reconcilement Of Tax Rates



	Year Ended December 31,
	2019		2018		2017
U.S. federal statutory tax rate	(21.0)	%	(21.0)	%	(35.0)	%
Valuation allowance	18.0		28.0		23.0
Tax reform	—		(2.0)		18.0
Credits	(2.0)		2.0		1.0
State tax benefit and other	5.0		(7.0)		(7.0)
Effective tax rate	—	%	—	%	—	%

Reconciliation Of Unrecognized Tax Benefit Accounts


	December 31,
	2019		2018		2017
Balance at the beginning of the year	$	877	$	512	$	213
Gross increases - tax positions in prior periods		—		—		37
Gross decreases - tax positions in prior periods		—		—		—
Gross increases - tax position in current period		593		365		262
Settlements		—		—		—
Lapses in statutes of limitations		—		—		—
Balance at the end of the year	$	1,470	$	877	$	512

Selected Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2019

Selected Quarterly Financial Data [Abstract]

Schedule Of Selected Quarterly Financial Data


	Quarter Ended
	2019								2018
	December 31,		September 30,		June 30,		March 31,		December 31,		September 30,		June 30,		March 31,
Revenue	$	—	$	—	$	—	$	—	$	—	$	—	$	—	$	—
Operating expenses:
General and administrative		7,174		5,606		5,146		4,401		3,814		5,675		5,173		5,383
Research and development		6,590		6,192		6,337		5,842		5,080		5,038		3,960		3,175
Amortization of intangible assets		167		166		166		167		166		166		167		166
Total operating expenses		13,931		11,964		11,649		10,410		9,060		10,879		9,300		8,724
Other income (expense):
Interest income		143		218		290		332		135		118		137		56
Other expense		—		—		—		—		(28)		—		—		—
Total other income		143		218		290		332		107		118		137		56
Loss from operations, before income taxes		(13,788)		(11,746)		(11,359)		(10,078)		(8,953)		(10,761)		(9,163)		(8,668)
Income tax benefit		—		—		—		—		—		—		—		—
Net loss		(13,788)		(11,746)		(11,359)		(10,078)		(8,953)		(10,761)		(9,163)		(8,668)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale securities, net of tax:		(4)		(14)		20		3		2		(3)		3		48
Comprehensive loss	$	(13,792)	$	(11,760)	$	(11,339)	$	(10,075)	$	(8,951)	$	(10,764)	$	(9,160)	$	(8,620)
Net loss per share
Basic and diluted net loss per share	$	(0.66)	$	(0.57)	$	(0.55)	$	(0.49)	$	(0.51)	$	(0.64)	$	(0.54)	$	(0.51)
Weighted average shares used to compute net loss per common share — basic and diluted		20,799		20,774		20,728		20,679		17,656		16,927		16,881		16,842

Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Stockholders Equity	$ 30,737,000				$ 66,334,000				$ 30,737,000	$ 66,334,000	$ 45,995,000		$ 25,298,000
Cash, cash equivalents, and investments	25,400,000								25,400,000
Cash used in operating activities									(34,185,000)	(23,896,000)	(11,087,000)
Proceeds from rights offering									30,000,000
General and administrative	7,174,000	$ 5,606,000	$ 5,146,000	$ 4,401,000	3,814,000	$ 5,675,000	$ 5,173,000	$ 5,383,000	22,327,000	20,045,000	15,503,000
Long-lived asset impairment									0	0	0
Patent costs									600,000	600,000	800,000
Liability for Uncertainty in Income Taxes, Noncurrent	0				0				0	0
Right-of-use assets	5,114,000								5,114,000
Lease liability	6,719,000								$ 6,719,000
Accounting Standards Update 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Right-of-use assets												$ 100,000
Lease liability												$ 100,000
Acquired Patents And Licenses [Member]
Summary Of Significant Accounting Policies [Line Items]
Intangible asset useful life									12 years
Maximum [Member] \| Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life									5 years
Minimum [Member] \| Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life									3 years
Accumulated Deficit [Member]
Summary Of Significant Accounting Policies [Line Items]
Stockholders Equity	$ (122,689,000)				$ (75,718,000)				$ (122,689,000)	$ (75,718,000)	$ (38,173,000)		$ (12,606,000)

Stockholders' Equity And Stock-Based Compensation (Narrative) (Details) - USD ($)					1 Months Ended	12 Months Ended
	Jan. 01, 2019	Dec. 06, 2018	Sep. 24, 2017	Feb. 07, 2017	Nov. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014	Oct. 25, 2018
Stockholders' Equity [Line Items]
Common stock, par value						$ 0.001	$ 0.001
Common stock, shares issued						20,825,000	20,593,000
Options granted						1,162,616
Warrants exercised						98,928
Exercise price						$ 16.33
Total intrinsic value of options exercised						$ 1,000,000	$ 1,800,000	$ 3,800,000
Fair value of options vested						8,400,000	6,400,000	26,800,000
Total stock-based compensation expense						11,287,000	$ 12,338,000	10,926,000
Unrecognized compensation cost						$ 14,200,000
Weighted average remaining contractual life						2 years 9 months 18 days
2017 Employee Stock Purchase Plan [Member]
Stockholders' Equity [Line Items]
Common stock, shares issued						38,279	23,869
Shares authorized							250,000
Increase in shares available for issuance threshold of common stock outstanding, number of shares							450,000
Increase in shares available for issuance threshold of common stock outstanding, percent outstanding							1.50%
Shares available for grant						440,195
2017 Inducement Equity Incentive Plan [Member]
Stockholders' Equity [Line Items]
Term period							10 years
Shares authorized					1,000,000
2017 Plan [Member]
Stockholders' Equity [Line Items]
Term period							10 years
Shares authorized							1,500,000
Additional common stock reserved for issuance	823,716
Increase in shares available for issuance threshold of common stock outstanding, number of shares							1,200,000
Increase in shares available for issuance threshold of common stock outstanding, percent outstanding							4.00%
Shares available for grant						998,288
First Vesting Portion [Member] \| 2017 Inducement Equity Incentive Plan [Member]
Stockholders' Equity [Line Items]
Vesting percentage							25.00%
Second Vesting Portion [Member] \| 2017 Inducement Equity Incentive Plan [Member]
Stockholders' Equity [Line Items]
Vesting period							36 months
Vesting percentage							8.33%
Sales, general and administrative [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense						$ 7,466,000	$ 9,004,000	9,136,000
Research and development [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense						3,821,000	$ 3,334,000	$ 1,790,000
Restricted Stock Units [Member]
Stockholders' Equity [Line Items]
Units granted during period							0
Reduction to APIC from shares withheld for tax							$ 100,000
Total stock-based compensation expense						$ 2,100,000	$ 2,900,000
Warrants to purchase common stock [Member]
Stockholders' Equity [Line Items]
Options granted
Warrants exercised						45,638
Aggregate intrinsic value exercisable options						$ 1,500,000
Performance Shares [Member]
Stockholders' Equity [Line Items]
Options granted						42,500
Directors [Member]
Stockholders' Equity [Line Items]
Total stock-based compensation expense					$ 1,200,000
Officer [Member] \| Restricted Stock Units [Member]
Stockholders' Equity [Line Items]
Cliff vest date						Jun. 30, 2018
Shares available for grant							160,974
Unrecognized compensation cost						$ 0
Certain Employees [Member] \| Restricted Stock Units [Member]
Stockholders' Equity [Line Items]
Shares available for grant							68,800
Total stock-based compensation expense						400,000	$ 100,000
Unrecognized compensation cost						$ 900,000
Certain Employees [Member] \| Restricted Stock Units [Member] \| First Vesting Portion [Member]
Stockholders' Equity [Line Items]
Vesting percentage							50.00%
Cliff vest date						Jun. 01, 2019
Certain Employees [Member] \| Restricted Stock Units [Member] \| Second Vesting Portion [Member]
Stockholders' Equity [Line Items]
Vesting percentage							50.00%
Cliff vest date						Jun. 01, 2021
Certain Employees [Member] \| Restricted Stock Units [Member] \| Change In Control [Member]
Stockholders' Equity [Line Items]
Vesting percentage							100.00%
Common Stock
Stockholders' Equity [Line Items]
Shares issued								2,820,000
Warrants exercised						99,000	145,000	162,000
Number of common shares called by issuance of warrants						37,320
Common Stock \| 2017 Inducement Equity Incentive Plan [Member]
Stockholders' Equity [Line Items]
Shares authorized						78,950
Common Stock \| Rights Offering [Member]
Stockholders' Equity [Line Items]
Net proceeds		$ 44,800,000
Right entitlement to holder		3,581,148								0.19860755
Exercise price of warrants/rights		$ 12.57								$ 12.57
Common Stock \| Warrants to purchase common stock [Member]
Stockholders' Equity [Line Items]
Warrants exercised						37,000	24,000	522,000
Common Stock \| Private Placement [Member]
Stockholders' Equity [Line Items]
Shares sold			2,000,000	819,673
Common stock, par value			$ 0.001	$ 0.001
Price per share			$ 15.02	$ 6.10
Net proceeds			$ 29,900,000	$ 5,000,000
Common Stock \| Chairman, Robert W. Duggan [Member] \| Rights Offering [Member]
Stockholders' Equity [Line Items]
Ownership percentage		35.00%					43.00%
Shares purchased		3,146,226
Investment		$ 39,500,000
MDB Capital Group, LLC [Member] \| Initial Public Offering [Member]
Stockholders' Equity [Line Items]
Price per share								$ 5.00
Warrants/rights outstanding						121,609
Exercisable period of warrants or rights						5 years
Number of common shares called by issuance of warrants								574,985
MDB Capital Group, LLC [Member] \| Private Placement [Member]
Stockholders' Equity [Line Items]
Price per share									$ 2.67
Warrants/rights outstanding						46,238
Exercisable period of warrants or rights									7 years
Number of common shares called by issuance of warrants									299,625

Stockholders' Equity And Stock-Based Compensation (Summary Of Stock Warrant Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Beginning Balance, Number of shares	2,956,687
Options granted, Number of shares	1,162,616
Options exercised, Number of shares	(98,928)
Options canceled, Number of shares	(99,669)
Options expired, Number of shares	(171,520)
Ending Balance, Number of shares	3,749,186	2,956,687
Beginning Balance, Weighted average exercise price per share	$ 17.04
Options granted, Weighted average exercise price per share	13.60
Options exercised, Weighted average exercise price per share	2.75
Options expired, Weighted average exercise price per share	21.61
Ending Balance, Weighted average exercise price per share	$ 16.18	$ 17.04
Weighted average remaining life	7 years 10 months 24 days	7 years 7 months 6 days
Warrants to purchase common stock [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Beginning Balance, Number of shares	213,485
Options granted, Number of shares
Options exercised, Number of shares	(45,638)
Options expired, Number of shares
Ending Balance, Number of shares	167,847	213,485
Beginning Balance, Weighted average exercise price per share	$ 4.00
Options granted, Weighted average exercise price per share
Options exercised, Weighted average exercise price per share	2.67
Options expired, Weighted average exercise price per share
Ending Balance, Weighted average exercise price per share	$ 4.36	$ 4.00
Weighted average remaining life	1 year 3 months 11 days	2 years 4 months 13 days

Stockholders' Equity And Stock-Based Compensation (Summary Of Stock Option Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Stockholders' Equity And Stock-Based Compensation [Abstract]
Beginning Balance, Number of shares	2,956,687
Options granted, Number of shares	1,162,616
Options exercised, Number of shares	(98,928)
Options canceled, Number of shares	(99,669)
Options expired, Number of shares	(171,520)
Ending Balance, Number of shares	3,749,186	2,956,687
Exercisable, Number of shares	2,110,219
Beginning Balance, Weighted average exercise price per share	$ 17.04
Options granted, Weighted average exercise price per share	13.60
Options exercised, Weighted average exercise price per share	2.75
Options canceled, Weighted average exercise price per share	15.66
Options expired, Weighted average exercise price per share	21.61
Ending Balance, Weighted average exercise price per share	16.18	$ 17.04
Exercisable, Weighted average exercise price per share	$ 16.33
Weighted average remaining life	7 years 10 months 24 days	7 years 7 months 6 days
Weighted average remaining life, exercisable	6 years 6 months

Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended								12 Months Ended
Income Taxes (Narrative) (Details) - USD ($)	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Loss from operations, before income taxes	$ (13,788,000)	$ (11,746,000)	$ (11,359,000)	$ (10,078,000)	$ (8,953,000)	$ (10,761,000)	$ (9,163,000)	$ (8,668,000)	$ (46,971,000)	$ (37,545,000)	$ (25,567,000)
Income tax provision (benefit)
Federal statutory tax rate									21.00%	21.00%	35.00%
Total unrecognized tax benefit	1,470,000				877,000				$ 1,470,000	$ 877,000	$ 512,000	$ 213,000
Accrued interest or penalties	0				0				$ 0	0	$ 0
Federal And California [Member]
Income Taxes [Line Items]
Net operating loss carryforwards					$ 62,200,000					$ 62,200,000
Net operating loss carryforward, expiration									2034
NOL, percent of taxable income									80.00%
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	87,800,000								$ 87,800,000
Research and development credit carryforward	2,400,000								$ 2,400,000
Research and developmen tax credit carryforward, expiration									2035
California [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	25,800,000								$ 25,800,000
Research and development credit carryforward	$ 2,000,000								$ 2,000,000

Selected Quarterly Financial Data (Schedule Of Selected Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Data [Abstract]
Revenue
Operating expenses:
General and administrative	$ 7,174	$ 5,606	$ 5,146	$ 4,401	$ 3,814	$ 5,675	$ 5,173	$ 5,383	22,327	20,045	15,503
Research and development	6,590	6,192	6,337	5,842	5,080	5,038	3,960	3,175	24,961	17,253	9,646
Amortization of intangible assets	167	166	166	167	166	166	167	166	666	665	665
Total operating expenses	13,931	11,964	11,649	10,410	9,060	10,879	9,300	8,724	47,954	37,963	25,814
Other income (expense):
Interest income	143	218	290	332	135	118	137	56	983	446	247
Other					(28)					(28)
Total other income	143	218	290	332	107	118	137	56	983	418	247
Loss from operations, before income taxes	(13,788)	(11,746)	(11,359)	(10,078)	(8,953)	(10,761)	(9,163)	(8,668)	(46,971)	(37,545)	(25,567)
Income tax benefit
Net loss	(13,788)	(11,746)	(11,359)	(10,078)	(8,953)	(10,761)	(9,163)	(8,668)	(46,971)	(37,545)	(25,567)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale securities, net of tax	(4)	(14)	20	3	2	(3)	3	48	5	50	(44)
Comprehensive loss	$ (13,792)	$ (11,760)	$ (11,339)	$ (10,075)	$ (8,951)	$ (10,764)	$ (9,160)	$ (8,620)	$ (46,966)	$ (37,495)	$ (25,611)
Basic and diluted net loss per share	$ (0.66)	$ (0.57)	$ (0.55)	$ (0.49)	$ (0.51)	$ (0.64)	$ (0.54)	$ (0.51)	$ (2.26)	$ (2.20)	$ (1.73)
Weighted average shares used to compute net loss per common share - basic and diluted	20,799	20,774	20,728	20,679	17,656	16,927	16,881	16,842	20,746	17,078	14,754

Consolidated Statements of Stockholders' Equity (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares
Rights [Member]
Price per share \| $ / shares	$ 12.57
Issuance costs \| $	$ 213

Description Of The Business	12 Months Ended
Description Of The Business	Dec. 31, 2019
Description Of The Business [Abstract]
Description Of The Business	1. Description of the Business Pulse Biosciences, Inc. (the Company) is a novel bioelectric medicine company committed to health innovation that improves and potentially extends the lives of patients. The Company is pursuing regulatory clearance to market its first product, its proprietary CellFX System. The Company’s CellFX System utilizes its patented Nano-Pulse Stimulation™ (NPS™) technology to treat a variety of applications for which an optimal solution remains unfulfilled. NPS is a proprietary technology that delivers nanosecond duration pulses of high amplitude electrical energy to non-thermally clear targeted cells while sparing adjacent non-cellular tissue. The cell-specific effects of NPS technology have been validated in a series of completed and ongoing clinical studies. The Company was incorporated in Nevada on May 19, 2014, and was reincorporated in the State of Delaware on June 18, 2018. The Company’s headquarters and research facility are located in Hayward, California. The Company’s activities are subject to significant risks and uncertainties, including the need for additional capital. The Company has not yet commenced any revenue-generating operations, does not have any cash flows from operations, and will need to raise additional capital to finance its operations. However, there can be no assurances that the Company will be able to obtain additional financing on acceptable terms and in the amounts necessary to fully fund its operating requirements.

Goodwill	12 Months Ended
Goodwill	Dec. 31, 2019
Goodwill [Abstract]
Goodwill	5. Goodwill In 2014, the Company acquired three companies (the acquisitions) for aggregate consideration of $5.5 million. In accordance with ASC Topic 805, Business Combinations, the Company recorded goodwill of $2.8 million in connection with the acquisitions, which represents the excess of consideration paid over the fair value of net tangible and intangible assets acquired. The Company reviews goodwill for impairment annually or whenever changes in circumstances indicate that the carrying amount of goodwill may not be recoverable. Based on the Company’s annual review as of December 31, 2019, the Company determined that its goodwill was not impaired.

Research Grants And Agreements	12 Months Ended
Research Grants And Agreements	Dec. 31, 2019
Research Grants And Agreements [Abstract]
Research Grants And Agreements	7. Research Grants and Agreements Sponsored Research Agreement The Company entered into a Sponsored Research Agreement (SRA) with ODURF during 2014 pursuant to which the Company sponsors research activities performed by ODURF’s Frank Reidy Center. ODURF is compensated by the Company for its conduct of each study in accordance with the budget and payment terms set forth in the applicable task order. During the years ended December 31, 2019, 2018 and 2017, the Company agreed to sponsor $0.8 million, $0.8 million and $0.7 million, respectively, in research during the subsequent 12-month period to be funded through monthly payments made upon ODURF certifying, to the Company’s reasonable satisfaction, that ODURF has met its obligations pursuant to the specified task order and statement of work. The principal investigator may transfer funds with the budget as needed without the Company’s approval so long as the obligations of ODURF under the task order and statement of work remain unchanged and unimpaired. As of December 31, 2019, $0.6 million remained payable under this research agreement. In addition, during the year ended December 31, 2017, the Company agreed to provide $0.3 million in research funding to researchers affiliated with ODURF and EVMS matching funds made available to those researchers by the Virginia Biosciences Health Research Corporation. The Company’s sponsorship affords access to certain intellectual property, if any, developed during the project. As of December 31, 2019, no amount remained payable under this agreement. During the years ended December 31, 2019, 2018 and 2017, the Company incurred costs relating to the SRA equal to $0.9 million, $0.7 million and $0.8 million, respectively.

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	9. Related Party Transactions Kenneth A. Clark, a director of the Company since November 2017, is a member of the law firm of Wilson Sonsini Goodrich and Rosati (WSGR), which is also serves as the outside corporate counsel to the Company. During the years ended December 31, 2019 and 2018, the Company incurred expenses reported in general and administrative expenses in the consolidated statement of operations for legal services rendered by WSGR totaling approximately $0.5 million and $1.2 million, respectively. During the year ended December 31, 2018, the Company capitalized approximately $0.1 million for legal expenses incurred in connection with the rights offering (Note 6). During December 2018, the Company completed a rights offering pursuant to which it sold an aggregate of 3,581,148 shares of its common stock, par value $0.001 per share, at a price per share of $12.57, for net proceeds of approximately $44.8 million. At the time of transaction, Robert W. Duggan, the Company’s Chairman of the Board of Directors and the beneficial owner of approximately 35% of the Company’s then outstanding common stock prior to the rights offering. After giving effect to the rights offering, Mr. Duggan was the beneficial owner or approximately 43% of the Company’s outstanding stock as of December 31, 2019.

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Consolidated Balance Sheets [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	20,825,000	20,593,000
Common stock, shares outstanding	20,825,000	20,593,000

Consolidated Statements Of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Private Placement [Member]
Issuance costs	$ 199
Rights [Member]
Issuance costs	$ 213	$ 213

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 31, 2019
Employee Benefit Plans [Abstract]
Employee Benefit Plans	11. Employee Benefit Plans The Company sponsors a defined contribution plan under which it may make discretionary contributions. The Company did not make any employer matching contributions to this plan during the years ended December 31, 2019, 2018 and 2017.

Investments And Fair Value Of Financial Instruments (Schedule Of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Cost	$ 18,495	$ 8,481
Gross Unrealized Gains	4
Gross Unrealized Losses		(1)
Fair Value	18,499	8,480
US Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost	18,495	8,481
Gross Unrealized Gains	4
Gross Unrealized Losses		(1)
Fair Value	$ 18,499	$ 8,480

Investments And Fair Value Of Financial Instruments (Fair Value Of Financial Assets Measured On A Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Total assets measured at fair value	$ 24,928	$ 59,183
Cash and cash equivalents [Member] \| Cash and money market funds [Member]
ASSETS
Total cash and cash equivalents	6,429	50,703
Investments [Member] \| U.S. government and agency securities [Member]
ASSETS
Total investments	18,499	8,480
Level 1 [Member]
ASSETS
Total assets measured at fair value	6,429	50,703
Level 1 [Member] \| Cash and cash equivalents [Member] \| Cash and money market funds [Member]
ASSETS
Total cash and cash equivalents	6,429	50,703
Level 2 [Member]
ASSETS
Total assets measured at fair value	18,499	8,480
Level 2 [Member] \| Investments [Member] \| U.S. government and agency securities [Member]
ASSETS
Total investments	$ 18,499	$ 8,480

Balance Sheet Components (Schedule Of Property And Equipment, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Equipment, gross	$ 4,052	$ 3,165
Less: Accumulated depreciation and amortization	(1,486)	(992)
Equipment, net	2,566	2,173
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Equipment, gross	2,248	2,248
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Equipment, gross	677	518
Furniture, Fixtures, And Equipment [Member]
Property, Plant and Equipment [Line Items]
Equipment, gross	466	248
Software [Member]
Property, Plant and Equipment [Line Items]
Equipment, gross	118	118
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Equipment, gross	$ 543	$ 33

Balance Sheet Components (Schedule Of Intangible Assets, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Less: Accumulated amortization	$ (3,438)	$ (2,772)
Intangible assets, net	4,547	5,213
Acquired Patents And Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 7,985	$ 7,985

Balance Sheet Components (Schedule Of Amortization Of Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Components [Abstract]
2020	$ 665
2021	665
2022	665
2023	665
2024	665
Thereafter	1,222
Intangible assets, net	$ 4,547	$ 5,213

Balance Sheet Components (Schedule Of Accrued Expenses) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Components [Abstract]
Compensation expense	$ 1,699	$ 938
Accrued clinical	262	156
Professional fees	51	274
Property and equipment	234
Other	250	53
Accrued expenses	$ 2,496	$ 1,421

Goodwill (Narrative) (Details) - USD ($)	12 Months Ended
Goodwill (Narrative) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2014	Dec. 31, 2018
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Goodwill	$ 2,791,000		$ 2,791,000
Goodwill impairment	$ 0
TPI, BEM And NB [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Aggregate consideration		$ 5,500,000
Goodwill		$ 2,800,000

Income Taxes (Components Of Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Abstract]
Temporary differences	$ 119	$ 111
Credits	4,409	5,330
Stock compensation	5,473	2,630
Lease liability under ASC 842	1,411
Net operating loss carryforwards	20,755	15,365
Total deferred tax assets before valuation allowance	32,167	23,436
Valuation allowance	(30,369)	(22,696)
Total deferred tax assets after valuation allowance	1,798	740
Technology deferred tax liability	(434)	$ (740)
Right of use assets under ASC 842	$ (1,364)

Income Taxes (Reconcilement Of Tax Rates) (Details)	12 Months Ended
Income Taxes (Reconcilement Of Tax Rates) (Details)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Abstract]
U.S. federal statutory tax rate	(21.00%)	(21.00%)	(35.00%)
Valuation allowance	18.00%	28.00%	23.00%
Tax reform		(2.0)	18.0
Permanent differences	(2.00%)	2.00%	1.00%
State tax benefit and other	5.00%	(7.00%)	(7.00%)

Commitments And Contingencies (Narrative) (Details) $ in Thousands	1 Months Ended		12 Months Ended
	Nov. 30, 2019 USD ($)	Jan. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)	Jan. 31, 2017 ft²
Commitments and Contingencies [Line Items]
Area Of Lease \| ft²							15,700
Lease term							5 years
Right-of-use assets			$ 5,114
Increase in other assets			393		$ 101
Rent expense, including common area maintenance charges			500	$ 200	$ 300
Accounting Standards Update 2016-02 [Member]
Commitments and Contingencies [Line Items]
Right-of-use assets						$ 100
Increase in right-of-use assets	$ 3,000	$ 2,000	5,100
Increase in lease liability			$ 6,700

Commitments And Contingencies (Schedule Of Future Minimum Lease Payments) (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Commitments And Contingencies [Abstract]
2020	$ 647
2021	986
2022	1,071
2023	1,094
Thereafter	7,190
Total lease payments	10,988
Less imputed interest	(4,269)
Total lease liabilities	$ 6,719

Employee Benefit Plans (Narrative) (Details) - USD ($)	12 Months Ended
Employee Benefit Plans (Narrative) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Benefit Plans [Abstract]
Employer matching contributions	$ 0	$ 0	$ 0