Shockwave Medical (SWAV) 10-Q 13 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	May 06, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Trading Symbol	SWAV
Entity Registrant Name	Shockwave Medical, Inc.
Entity Central Index Key	0001642545
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		31,860,263
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity File Number	001-38829
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-0494101
Entity Address, Address Line One	5403 Betsy Ross Drive
Entity Address, City or Town	Santa Clara
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95054
City Area Code	510
Local Phone Number	279-4262
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Title of 12(b) Security	Shockwave Medical, Inc., common stock, par value $0.001 per share
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
CURRENT ASSETS:
Cash and cash equivalents	$ 123,111	$ 139,045
Short-term investments	47,278	56,304
Accounts receivable, net	7,811	7,377
Inventory	15,921	12,074
Prepaid expenses and other current assets	3,485	1,897
Total current assets	197,606	216,697
Operating lease right-of-use assets	8,495	8,825
Property and equipment, net	13,084	4,910
Other assets	1,553	1,506
TOTAL ASSETS	220,738	231,938
CURRENT LIABILITIES:
Accounts payable	2,150	2,790
Term notes, current portion		6,667
Accrued liabilities	15,826	13,777
Lease liability, current portion	787	774
Total current liabilities	18,763	24,008
Lease liability, noncurrent portion	8,077	8,125
Term notes, noncurrent portion	16,126	7,152
TOTAL LIABILITIES	42,966	39,285
Commitments and contingencies
STOCKHOLDERS’ EQUITY:
Preferred stock
Common stock	32	31
Additional paid-in capital	374,386	370,561
Accumulated other comprehensive income	103	35
Accumulated deficit	(196,749)	(177,974)
TOTAL STOCKHOLDERS’ EQUITY	177,772	192,653
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 220,738	$ 231,938

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue:
Product revenue	$ 15,197	$ 7,269
Type of Revenue [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember
Cost of revenue:
Cost of product revenue	$ 5,651	$ 3,072
Type of Cost, Good Or Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember
Gross profit	$ 9,546	$ 4,197
Operating expenses:
Research and development	11,890	7,484
Sales and marketing	10,411	5,871
General and administrative	6,224	3,001
Total operating expenses	28,525	16,356
Loss from operations	(18,979)	(12,159)
Interest expense	(277)	(245)
Change in fair value of warrant liability		(609)
Other income, net	504	221
Net loss before taxes	(18,752)	(12,792)
Income tax provision	23	7
Net loss	(18,775)	(12,799)
Unrealized gain on available-for-sale securities	68
Total comprehensive loss	$ (18,707)	$ (12,799)
Net loss per share, basic and diluted	$ (0.59)	$ (1.37)
Shares used in computing net loss per share, basic and diluted	31,644,041	9,364,755

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning balance at Dec. 31, 2018	$ (122,588)		$ 2	$ 4,275		$ (126,865)
Temporary equity, Beginning balance, Shares at Dec. 31, 2018		18,670,328
Temporary equity, Beginning balance at Dec. 31, 2018		$ 152,806
Beginning balance, Shares at Dec. 31, 2018			1,824,852
Exercise of common stock warrants for cash	110			110
Exercise of common stock warrants for cash, Shares			50,331
Issuance of common stock upon net exercise of warrants	133			133
Issuance of common stock upon net exercise of warrants, Shares			101,744
Conversion of preferred stock to common stock upon initial public offering	152,806		$ 18	152,788
Temporary equity, Conversion of preferred stock to common stock upon initial public offering, Shares		(18,670,328)
Temporary equity, Conversion of preferred stock to common stock upon initial public offering		$ (152,806)
Conversion of preferred stock to common stock upon initial public offering, Shares			18,670,328
Conversion of Series A-1 warrants to common stock warrants upon initial public offering	789			789
Issuance of common stock in connection with initial public offering, net of issuance costs of $11.3 million	100,139		$ 7	100,132
Issuance of common stock in connection with initial public offering, net of issuance costs, Shares			6,555,000
Issuance of common stock in connection with private placement	10,000		$ 1	9,999
Issuance of common stock in connection with private placement, Shares			588,235
Exercise of stock options	169			169
Exercise of stock options, Shares			80,515
Vesting of early exercised options	18			18
Stock-based compensation	412			412
Settlement of fractional shares resulting from reverse stock split	(3)			(3)
Settlement of fractional shares resulting from reverse stock split, Shares			(114)
Net loss	(12,799)					(12,799)
Ending balance at Mar. 31, 2019	129,186		$ 28	268,822		(139,664)
Beginning balance, shares at Mar. 31, 2019			27,870,891
Beginning balance at Dec. 31, 2019	192,653		$ 31	370,561	$ 35	(177,974)
Beginning balance, Shares at Dec. 31, 2019			31,446,787
Exercise of stock options	$ 1,113		$ 1	1,112
Exercise of stock options, Shares	356,128		356,128
Unrealized gain on available-for- sale securities	$ 68				68
Issuance of common stock under employee stock purchase plan	842			842
Issuance of common stock under employee stock purchase plan, Share			24,691
Stock-based compensation	1,871			1,871
Net loss	(18,775)					(18,775)
Ending balance at Mar. 31, 2020	$ 177,772		$ 32	$ 374,386	$ 103	$ (196,749)
Beginning balance, shares at Mar. 31, 2020			31,827,606

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Statement Of Stockholders Equity [Abstract]
Issuance costs, initial public offering	$ 11.3

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (18,775)	$ (12,799)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	426	255
Stock-based compensation	1,871	412
Amortization of right-of-use assets	369	249
Accretion of discount on available-for-sale securities	114
Loss on write down of fixed assets		19
Change in fair value of warrant liability		609
Amortization of debt issuance costs	153	104
Changes in operating assets and liabilities:
Accounts receivable	(434)	(1,089)
Inventory	(3,807)	(1,883)
Prepaid expenses and other current assets	(1,588)	(1,396)
Other assets	(47)	(19)
Accounts payable	(542)	369
Accrued and other current liabilities	(1,855)	991
Lease liabilities	(74)	(237)
Net cash used in operating activities	(24,189)	(14,415)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of available-for-sale securities	(16,020)
Proceeds from maturities of available-for-sale securities	25,000
Purchase of property and equipment	(4,655)	(420)
Net cash provided by (used in) investing activities	4,325	(420)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock upon initial public offering, net of issuance costs paid		102,977
Proceeds from issuance of common stock in private placement		10,000
Payments of offering costs	(179)
Principal payments of term loan	(1,111)
Net proceeds from term loan	3,265
Proceeds from stock option exercises	1,113	169
Proceeds from issuance of common stock under employee stock purchase plan	842
Proceeds from warrant exercises		110
Net cash provided by financing activities	3,930	113,256
Net (decrease) increase in cash, cash equivalents and restricted cash	(15,934)	98,421
Cash, cash equivalents and restricted cash at beginning of period	140,495	40,093
Cash, cash equivalents and restricted cash equivalents at end of period	124,561	138,514
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest paid	108	132
Income tax paid		4
NON-CASH INVESTING AND FINANCING ACTIVITIES:
Common stock issued on conversion of convertible preferred stock		152,806
Common stock issued upon net exercise of warrants		133
Common stock warrants issued on conversion of preferred stock warrants and the reclassification of the warrant liability		789
Deferred offering costs included in accounts payable and accrued liabilities		2,215
Right-of-use asset obtained in exchange for lease liability	39	73
Property and equipment purchases included in accounts payable and accrued liabilities	4,036	$ 93
Transfer of fixed assets to inventory	$ 40

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Shockwave Medical, Inc. (the “Company”) was incorporated on June 17, 2009. The Company is primarily engaged in the development of Intravascular Lithotripsy (“IVL”) technology for the treatment of calcified plaque in patients with peripheral vascular, coronary vascular and heart valve disease. Built on a balloon catheter platform, the IVL technology uses lithotripsy to disrupt both superficial and deep vascular calcium, while minimizing soft tissue injury, and an integrated angioplasty balloon to dilate blockages at low pressures, restoring blood flow. In 2016, the Company began commercial and manufacturing operations, and began selling catheters based on the IVL technology. The Company’s headquarters are in Santa Clara, California. The Company is located and operates primarily in the United States and has a subsidiary in Germany. Need for Additional Capital The Company has incurred significant losses and has negative cash flows from operations. As of March 31, 2020, the Company had an accumulated deficit of $196.7 million. Management expects to continue to incur additional substantial losses for the foreseeable future. As of March 31, 2020, the Company had cash, cash equivalents and short-term investments of $170.4 million, which are available to fund future operations. The Company believes that its cash, cash equivalents and short-term investments as of March 31, 2020, will be sufficient for the Company to continue as a going concern for at least 12 months from the date the unaudited condensed consolidated financial statements are filed with the Securities and Exchange Commission (“SEC”). The Company’s future capital requirements will depend on many factors, including its growth rate, the timing and extent of its spending to support research and development activities, the timing and cost of establishing additional sales and marketing capabilities and the impact of the COVID-19 pandemic. Risk and Uncertainties The Company is subject to risks and uncertainties as a result of the COVID-19 pandemic. In March 2020, the World Health Organization characterized COVID-19 as a pandemic and the President of the United States declared the COVID-19 outbreak a national emergency. There are many uncertainties regarding the current COVID-19 pandemic, and the Company is closely monitoring the impact of the pandemic on all aspects of its business, including how it will impact its customers, patients that would benefit from procedures utilizing the Company’s products, employees, suppliers, vendors, business partners and distribution channels. The capital markets and economies worldwide have been negatively impacted by the COVID-19 pandemic, and it is possible that it could cause a local and/or global economic recession. As such he Company's future results of operations and liquidity could be adversely impacted by a variety of factors related to the COVID-19 pandemic, including those discussed in the section entitled “ Risk Factors ” of this Quarterly Report on Form 10-Q. As of the date of issuance of these condensed consolidated financial statements, the extent to which the COVID-19 pandemic may materially impact the Company's financial condition, liquidity, or results of operations is uncertain.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of SEC regarding interim financial reporting. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s consolidated financial position, results of operations and cash flows. The results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results to be expected for the year ending December 31, 2020 or for any other future annual or interim period. The condensed consolidated balance sheet as of December 31, 2019 included herein was derived from the audited financial statements as of that date. The unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, filed with the SEC on March 12, 2020. Reclassifications Certain amounts in the prior period condensed consolidated financial statements have been reclassified to conform to the current period presentation. Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market accounts. Restricted cash as of March 31, 2020 and December 31, 2019 relates to a letter of credit established for the Company’s office lease and is recorded as other assets on the condensed consolidated balance sheets. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed consolidated balance sheets that sum to the total of the same amounts shown in the condensed consolidated statements of cash flows: March 31, 2020 December 31, 2019 (in thousands) Cash and cash equivalents $ 123,111 $ 139,045 Restricted cash 1,450 1,450 Total cash, cash equivalents, and restricted cash $ 124,561 $ 140,495 Short-Term Investments Short-term investments have been classified as available-for-sale and are carried at estimated fair value based upon quoted market prices or pricing models for similar securities. The Company determines the appropriate classification of its investments in debt securities at the time of purchase. Available-for-sale securities with original maturities beyond three months at the date of purchase are classified as current based on their availability for use in current operations. Unrealized gains and losses are excluded from earnings and are reported as a component of comprehensive loss, except for credit-related impairment losses. The Company periodically evaluates whether declines in fair values of its marketable securities below their book value are other-than-temporary and if they are related to deterioration in credit risk. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company’s ability and intent to hold the marketable security until a forecasted recovery occurs. The Company also assesses whether it has plans to sell the security or it is more likely than not it will be required to sell any marketable securities before recovery of its amortized cost basis. Realized gains and losses and declines in fair value judged to be other than temporary, if any, on marketable securities are included in other income, net. Effective January 1, 2020, any unrealized losses on available-for-sale debt securities that are attributed to credit risk are recorded to earnings through an allowance for credit losses. The cost of investments sold is based on the specific-identification method. Interest on marketable securities is included in other income, net. Fair Value of Financial Instruments The Company’s cash and cash equivalents, restricted cash, short-term investments, accounts receivable, accounts payable and accrued liabilities approximate their fair value due to their short maturities. Management believes that its term notes bear interest at the prevailing market rates for instruments with similar characteristics; accordingly, the carrying value of this instrument approximates its fair value. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines the fair value of its financial instruments based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: Level 1 – Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2 – Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and Level 3 – Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data. Revenue The Company records product revenue primarily from the sale of its IVL catheters. The Company sells its products to hospitals, primarily through direct sales representatives, as well as through distributors in selected international markets. Additionally, a significant portion of the Company’s revenue is generated through a consignment model under which inventory is maintained at hospitals. Revenue is recognized when a customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. For products sold through direct sales representatives, control is transferred upon delivery to customers. For products sold to distributors internationally and products sold to customers that utilize stocking orders, control is transferred upon shipment or delivery to the customer’s named location, based on the contractual shipping terms. For consignment inventory, control is transferred at the time the IVL catheters are consumed in a procedure. The Company generally provides for the use of an IVL generator and connector cable under an agreement to customers at no charge to facilitate use of the IVL catheters. These agreements do not contain contractually enforceable minimum commitments and are generally cancellable by either party with 30 days’ notice. Recently Adopted Accounting Pronouncements Effective January 1, 2020, the Company adopted ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In addition, Topic 326 also provides new guidance related to the measurement of expected credit losses on the Company’s allowance for bad debt for accounts receivable, which is estimated upon assessment of various factors including historical collection experience, current and future economic market conditions and a review of the current aging status and financial condition of the Company’s customers. During the three months ended March 31, 2020, the Company recorded an additional allowance for bad debt in response to an assessment of the evolving credit environment under the COVID-19 pandemic. The Company will continue to update its estimate of credit losses from accounts receivable in future periods in response to the uncertainties caused by the COVID-19 pandemic.

Financial Instruments and Fair

Financial Instruments and Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Measurements	3. Financial Instruments and Fair Value Measurements The following tables summarize the Company’s financial assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy: March 31, 2020 Level 1 Level 2 Level 3 Total (in thousands) Assets: U.S. Treasury securities $ 36,267 $ — $ — $ 36,267 Money market funds 110,893 — — 110,893 Commercial paper — 10,968 — 10,968 Corporate bonds — 5,043 — 5,043 Total assets $ 147,160 $ 16,011 $ — $ 163,171 December 31, 2019 Level 1 Level 2 Level 3 Total (in thousands) Assets: U.S. Treasury securities $ 43,245 $ — $ — $ 43,245 Money market funds 29,386 — — 29,386 Reverse repurchase agreements — 10,000 — 10,000 Commercial paper — 6,958 — 6,958 Corporate bonds — 8,096 — 8,096 Total assets $ 72,631 $ 25,054 $ — $ 97,685 The Company’s convertible preferred stock warrants were converted into common stock warrants upon the closing of an initial public offering of the Company’s common stock (“IPO”) in March 2019. The change in the fair value of the warrant liability for the three months ended March 31, 2019 is summarized below (in thousands): Balance at December 31, 2018 $ 313 Change in fair value of warrant liability 609 Net exercise of warrants (133 ) Conversion of Series A preferred stock warrants to common stock warrants upon the closing of the IPO (789 ) Balance at March 31, 2019 $ — The valuation of the Company’s convertible preferred stock warrant liability contains unobservable inputs that reflect the Company’s own assumptions for which there is little, if any, market activity for at the measurement date. Accordingly, the Company’s convertible preferred stock warrant liability is measured at fair value on a recurring basis using unobservable inputs and are classified as Level 3 inputs, and any change in fair value is recognized as change in fair value of warrant liability in the condensed consolidated statements of operations and comprehensive loss. The fair value of the warrants was determined using the Black-Scholes option pricing model and the following assumptions: March 31, 2019 Expected term (in years) 5.3 Expected volatility 43.9% Risk-free interest rate 2.5% Expected dividend yield 0%

Cash Equivalents and Short-Term

Cash Equivalents and Short-Term Investments	3 Months Ended
	Mar. 31, 2020
Cash And Cash Equivalents [Abstract]
Cash Equivalents and Short-Term Investments	4. Cash Equivalents and Short-Term Investments The following is a summary of the Company’s cash equivalents and short-term investments: March 31, 2020 Amortized Cost Basis Unrealized Gains Unrealized Losses Fair Value (in thousands) U.S. Treasury securities $ 36,160 $ 107 $ — $ 36,267 Money market funds 110,893 — — 110,893 Commercial paper 10,968 — — 10,968 Corporate bonds 5,047 — (4 ) 5,043 Total $ 163,068 $ 107 $ (4 ) $ 163,171 Reported as: Cash equivalents $ 115,893 Short-term investments 47,278 Total $ 163,171 December 31, 2019 Amortized Cost Basis Unrealized Gains Unrealized Losses Fair Value (in thousands) U.S. Treasury securities $ 43,219 $ 27 $ (1 ) $ 43,245 Money market funds 29,386 — — 29,386 Reverse repurchase agreements 10,000 — — 10,000 Commercial paper 6,958 — — 6,958 Corporate bonds 8,087 9 — 8,096 Total $ 97,650 $ 36 $ (1 ) $ 97,685 Reported as: Cash equivalents $ 41,381 Short-term investments 56,304 Total $ 97,685 The Company recognized no material gains or losses on its cash equivalents and short-term investments in the periods presented. As of March 31, 2020, the remaining contractual maturities for available-for-sale securities were less than one year.

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	5. Balance Sheet Components Inventory Inventory consists of the following: March 31, December 31, 2020 2019 (in thousands) Raw material $ 2,726 $ 2,501 Work in progress 2,044 1,364 Finished goods 9,532 6,642 Consigned inventory 1,619 1,567 Total inventory $ 15,921 $ 12,074 Accrued Liabilities Accrued liabilities consist of the following: March 31, December 31, 2020 2019 (in thousands) Accrued employee compensation $ 4,835 $ 8,139 Accrued asset purchases 4,377 — Accrued research and development costs 4,100 3,090 Accrued professional services 1,361 804 Other 1,153 1,744 Total accrued liabilities $ 15,826 $ 13,777

Term Notes

Term Notes	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Term Notes	6. Term Notes Loan and Security Agreement In February 2018, the Company entered into a Loan and Security Agreement with Silicon Valley Bank (the “Loan and Security Agreement”). The terms of the Loan and Security Agreement included a term loan of $15.0 million and a revolving line of credit of $2.0 million. The term loan was available in two tranches, of which the first tranche of $10.0 million was funded in June 2018 and the second tranche of $5.0 million was funded in December 2018. The term loan accrued interest at a floating per annum rate equal to the greater of the Wall Street Journal prime rate minus 1.75% and 2.75%. There was a final payment equal to 6.75% of the original aggregate principal amount, or $1.0 million, of the term loan advances, which was being accrued over the expected term of the loan using the effective-interest method. In connection with the execution of the Loan and Security Agreement, the Company issued warrants to Silicon Valley Bank to purchase 34,440 shares of the Company’s common stock. Upon issuance, the fair value of the warrants of $0.1 million was recorded as a debt issuance cost. The debt issuance cost was being amortized to interest expense, net over the expected repayment period of the loan. In February 2020, the Company entered into a First Amendment to its Loan and Security Agreement (the “Amended Credit Facility”) to refinance its existing term loan, which is accounted for as a modification of the Loan and Security Agreement. Under the Amended Credit Facility, the existing revolving line of credit of $2.0 million was terminated and the termination fee of less than $0.1 million was waived. The Amended Credit Facility provides the Company with a supplemental term loan in the amount of $16.5 million. The Company received net proceeds of $3.3 million, which reflects an additional $4.3 million in principal as of the date of the modification less the final balloon payment fee of $1.0 million. The principal amount outstanding under the supplemental term loan accrues interest at a floating per annum rate equal to the greater of the Prime Rate minus 1.25% and 3.5% (3.5% as of March 31, 2020). The supplemental term loan matures on December 1, 2023. The Amended Credit Facility provides an interest-only payments period through either (a) June 30, 2021, if the Company does not achieve a certain financial performance target on or before June 30, 2021 (“Performance Milestone One”), or (b) December 31, 2021, if the Company achieves Performance Milestone One but does not achieve both of a certain regulatory milestone and a certain financial performance target on or before December 31, 2021 (“Performance Milestone Two”) or (c) until June 30, 2022, if the Company achieves both Performance Milestones. The additional final payment for the Amended Credit Facility is $1.6 million, which will be accrued over the term of the supplemental term loan using an effective interest rate that reflects the revised cash flows of the modified term loan. During the three months ended March 31, 2020 and 2019, the Company recorded interest expense related to the Amended Credit Facility and Loan and Security Agreement of $0.1 million and $0.1 million, respectively. Debt discount amortized as interest expense was $0.2 million and $0.1 million for the three months ended March 31, 2020 and 2019, respectively. The supplemental term loan is secured by all of the Company’s assets, excluding intellectual property and certain other assets. The loan contains customary affirmative and restrictive covenants, including with respect to the Company’s ability to enter into fundamental transactions, incur additional indebtedness, grant liens, pay any dividend or make any distributions to its holders, make investments, merge or consolidate with any other person or engage in transactions with the Company’s affiliates, but does not include any financial covenants. Long-term debt and net discount or premium balances are as follows: March 31, December 31, 2020 2019 (in thousands) Principal amount of term note $ 16,500 $ 13,334 Net (discount) premium associated with accretion of final payment, issuance of common stock warrants, and other debt issuance costs (374 ) 485 Term note, current and noncurrent 16,126 13,819 Less term note, current portion — (6,667 ) Term note, noncurrent portion $ 16,126 $ 7,152 Future minimum payments of principal and estimated payments of interest on the Company’s outstanding variable rate borrowings as of March 31, 2020 are as follows: Year ending December 31: (in thousands) 2020 (remainder) $ 441 2021 3,861 2022 6,961 2023 8,294 Total future payments 19,557 Less amounts representing interest (1,489 ) Less final payment (1,568 ) Total principal amount of term note payments $ 16,500

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	7. Stock-Based Compensation Total stock-based compensation was as follows: Three Months March 31, 2020 2019 (in thousands) Cost of product revenue $ 161 $ 27 Research and development 488 72 Sales and marketing 559 108 General and administrative 663 205 Total stock-based compensation $ 1,871 $ 412 Determination of Fair Value The Company estimates the grant-date fair value of the Company’s option awards using the Black-Scholes option pricing model. The assumptions for the Black-Scholes model for the three months ended March 31, 2020 and 2019 were as follows: Three Months Ended March 31, 2020 2019 Expected term (in years) 6.08 6.08 Expected volatility 42.4%-42.9% 42.4%-42.9% Risk-free interest rate 2.4%-2.6% 2.5%-2.6% Expected dividend yield 0% 0% 2009 Equity Incentive Plan and 2019 Equity Incentive Plan On June 17, 2009, the Company adopted the 2009 Equity Incentive Plan (the “2009 Plan”) under which the Board had the authority to issue stock options to employees, directors and consultants. In February 2019, the Company adopted the 2019 Stock Option and Incentive Plan (the “2019 Plan”), which became effective in connection with the IPO. As a result, effective as of March 6, 2019, the Company may not grant any additional awards under the 2009 Plan. The 2009 Plan will continue to govern outstanding equity awards granted thereunder. The Company initially reserved 2,000,430 shares of common stock for the issuance of a variety of awards under the 2019 Plan, including stock options, stock appreciation rights, awards of restricted stock and awards of restricted stock units In addition, the number of shares of common stock reserved for issuance under the 2019 Plan will automatically increase on the first day of January for a period of up to ten years, commencing on January 1, 2020, in an amount equal to 3% of the total number of shares of the Company’s capital stock outstanding on the last day of the preceding year, or a lesser number of shares determined by the Company’s board of directors. Stock Options Option activity under the 2009 Plan and 2019 Plan is set forth below: Shares Available for Grant Number of Shares Weighted- Average Exercise Price Per Share Weighted- Average Remaining Term Aggregate Intrinsic Value (in years) (in thousands) Balance, December 31, 2019 1,704,244 3,315,001 $ 5.08 7.28 $ 128,774 Awards authorized 943,345 — Options exercised — (356,128 ) 3.12 Options cancelled 13,339 (13,339 ) 3.90 Balance, March 31, 2020 2,660,928 2,945,534 $ 5.33 7.33 $ 82,046 Vested and exercisable, March 31, 2020 1,637,003 $ 3.93 6.76 $ 47,876 Vested and expected to vest, March 31, 2020 2,945,534 $ 5.33 7.33 $ 82,046 Restricted Stock Units Restricted stock units (“RSUs”) are share awards that entitle the holder to receive freely tradable shares of the Company’s common stock upon vesting. The RSUs cannot be transferred and the awards are subject to forfeiture if the holder’s employment terminates prior to the release of the vesting restrictions. The RSUs generally vest over a four-year period with straight-line vesting and a 25% one year cliff or over a three year period in equal amounts on a semi-annual basis, provided the employee remains continuously employed with the Company. The fair value of the RSUs is equal to the closing price of the Company’s common stock on the grant date. RSU activity under the 2019 Plan is set forth below : Number of Shares Weighted- Average Grant Date Fair Value Per Share Balance, December 31, 2019 280,904 $ 38.12 RSUs granted 445,205 42.14 RSUs forfeited (3,700 ) 37.19 Balance, March 31, 2020 722,409 $ 40.60 Employee Share Purchase Plan (ESPP) In February 2019, the Company adopted the 2019 Employee Stock Purchase Plan (“ESPP”), which became effective as of March 6, 2019. The Company initially reserved 300,650 shares of common stock for purchase under the ESPP. Each offering to the employees to purchase stock under the ESPP will begin on each September 1 and March 1 and will end on the following February 28 or 29 and August 30, respectively. The first offering period began on September 1, 2019 and ended on February 29, 2020. The fair value of the ESPP shares is estimated using the Black-Scholes option pricing model. The Company recorded $191,000 of stock-based compensation expense related to the ESPP for the three months ended March 31, 2020. At March 31, 2020, a total of 590,407 shares were available for issuance under the ESPP

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Net Loss Per Share	8. Net Loss Per Share The following outstanding potentially dilutive common stock equivalents have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect: March 31, 2020 2019 Common stock options issued and outstanding 2,945,534 3,960,505 Restricted stock units 722,409 5,328 Common stock warrants — 89,343 Total 3,667,943 4,055,176

Segment and Geographic Informat

Segment and Geographic Information	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Segment and Geographic Information	9. Segment and Geographic Information The following table represents the Company’s product revenue based on the location to which the product is shipped: Three Months Ended March 31, 2020 2019 (in thousands) United States $ 7,769 $ 3,636 Germany 911 643 Rest of Europe 5,108 2,736 All other countries 1,409 254 Product revenue $ 15,197 $ 7,269 As of March 31, 2020 and 2019, the Company’s long-lived assets were all held in the United States with the exception of certain equipment on loan to customers held internationally, which was not material as of each period end.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Risk and Uncertainties	Risk and Uncertainties The Company is subject to risks and uncertainties as a result of the COVID-19 pandemic. In March 2020, the World Health Organization characterized COVID-19 as a pandemic and the President of the United States declared the COVID-19 outbreak a national emergency. There are many uncertainties regarding the current COVID-19 pandemic, and the Company is closely monitoring the impact of the pandemic on all aspects of its business, including how it will impact its customers, patients that would benefit from procedures utilizing the Company’s products, employees, suppliers, vendors, business partners and distribution channels. The capital markets and economies worldwide have been negatively impacted by the COVID-19 pandemic, and it is possible that it could cause a local and/or global economic recession. As such he Company's future results of operations and liquidity could be adversely impacted by a variety of factors related to the COVID-19 pandemic, including those discussed in the section entitled “ Risk Factors ” of this Quarterly Report on Form 10-Q. As of the date of issuance of these condensed consolidated financial statements, the extent to which the COVID-19 pandemic may materially impact the Company's financial condition, liquidity, or results of operations is uncertain.
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of SEC regarding interim financial reporting. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s consolidated financial position, results of operations and cash flows. The results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results to be expected for the year ending December 31, 2020 or for any other future annual or interim period. The condensed consolidated balance sheet as of December 31, 2019 included herein was derived from the audited financial statements as of that date. The unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, filed with the SEC on March 12, 2020.
Reclassifications	Reclassifications Certain amounts in the prior period condensed consolidated financial statements have been reclassified to conform to the current period presentation.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market accounts. Restricted cash as of March 31, 2020 and December 31, 2019 relates to a letter of credit established for the Company’s office lease and is recorded as other assets on the condensed consolidated balance sheets. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed consolidated balance sheets that sum to the total of the same amounts shown in the condensed consolidated statements of cash flows: March 31, 2020 December 31, 2019 (in thousands) Cash and cash equivalents $ 123,111 $ 139,045 Restricted cash 1,450 1,450 Total cash, cash equivalents, and restricted cash $ 124,561 $ 140,495
Short-Term Investments	Short-Term Investments Short-term investments have been classified as available-for-sale and are carried at estimated fair value based upon quoted market prices or pricing models for similar securities. The Company determines the appropriate classification of its investments in debt securities at the time of purchase. Available-for-sale securities with original maturities beyond three months at the date of purchase are classified as current based on their availability for use in current operations. Unrealized gains and losses are excluded from earnings and are reported as a component of comprehensive loss, except for credit-related impairment losses. The Company periodically evaluates whether declines in fair values of its marketable securities below their book value are other-than-temporary and if they are related to deterioration in credit risk. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company’s ability and intent to hold the marketable security until a forecasted recovery occurs. The Company also assesses whether it has plans to sell the security or it is more likely than not it will be required to sell any marketable securities before recovery of its amortized cost basis. Realized gains and losses and declines in fair value judged to be other than temporary, if any, on marketable securities are included in other income, net. Effective January 1, 2020, any unrealized losses on available-for-sale debt securities that are attributed to credit risk are recorded to earnings through an allowance for credit losses. The cost of investments sold is based on the specific-identification method. Interest on marketable securities is included in other income, net.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s cash and cash equivalents, restricted cash, short-term investments, accounts receivable, accounts payable and accrued liabilities approximate their fair value due to their short maturities. Management believes that its term notes bear interest at the prevailing market rates for instruments with similar characteristics; accordingly, the carrying value of this instrument approximates its fair value. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines the fair value of its financial instruments based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: Level 1 – Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2 – Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and Level 3 – Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data.
Revenue	Revenue The Company records product revenue primarily from the sale of its IVL catheters. The Company sells its products to hospitals, primarily through direct sales representatives, as well as through distributors in selected international markets. Additionally, a significant portion of the Company’s revenue is generated through a consignment model under which inventory is maintained at hospitals. Revenue is recognized when a customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. For products sold through direct sales representatives, control is transferred upon delivery to customers. For products sold to distributors internationally and products sold to customers that utilize stocking orders, control is transferred upon shipment or delivery to the customer’s named location, based on the contractual shipping terms. For consignment inventory, control is transferred at the time the IVL catheters are consumed in a procedure. The Company generally provides for the use of an IVL generator and connector cable under an agreement to customers at no charge to facilitate use of the IVL catheters. These agreements do not contain contractually enforceable minimum commitments and are generally cancellable by either party with 30 days’ notice.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Effective January 1, 2020, the Company adopted ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In addition, Topic 326 also provides new guidance related to the measurement of expected credit losses on the Company’s allowance for bad debt for accounts receivable, which is estimated upon assessment of various factors including historical collection experience, current and future economic market conditions and a review of the current aging status and financial condition of the Company’s customers. During the three months ended March 31, 2020, the Company recorded an additional allowance for bad debt in response to an assessment of the evolving credit environment under the COVID-19 pandemic. The Company will continue to update its estimate of credit losses from accounts receivable in future periods in response to the uncertainties caused by the COVID-19 pandemic.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed consolidated balance sheets that sum to the total of the same amounts shown in the condensed consolidated statements of cash flows: March 31, 2020 December 31, 2019 (in thousands) Cash and cash equivalents $ 123,111 $ 139,045 Restricted cash 1,450 1,450 Total cash, cash equivalents, and restricted cash $ 124,561 $ 140,495

Financial Instruments and Fai_2

Financial Instruments and Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value	The following tables summarize the Company’s financial assets and liabilities measured at fair value on a recurring basis by level within the fair value hierarchy: March 31, 2020 Level 1 Level 2 Level 3 Total (in thousands) Assets: U.S. Treasury securities $ 36,267 $ — $ — $ 36,267 Money market funds 110,893 — — 110,893 Commercial paper — 10,968 — 10,968 Corporate bonds — 5,043 — 5,043 Total assets $ 147,160 $ 16,011 $ — $ 163,171 December 31, 2019 Level 1 Level 2 Level 3 Total (in thousands) Assets: U.S. Treasury securities $ 43,245 $ — $ — $ 43,245 Money market funds 29,386 — — 29,386 Reverse repurchase agreements — 10,000 — 10,000 Commercial paper — 6,958 — 6,958 Corporate bonds — 8,096 — 8,096 Total assets $ 72,631 $ 25,054 $ — $ 97,685
Schedule of Change in the Fair Value of the Warrant Liability	The Company’s convertible preferred stock warrants were converted into common stock warrants upon the closing of an initial public offering of the Company’s common stock (“IPO”) in March 2019. The change in the fair value of the warrant liability for the three months ended March 31, 2019 is summarized below (in thousands): Balance at December 31, 2018 $ 313 Change in fair value of warrant liability 609 Net exercise of warrants (133 ) Conversion of Series A preferred stock warrants to common stock warrants upon the closing of the IPO (789 ) Balance at March 31, 2019 $ —
Fair Value of Warrants Using Black-Scholes Option Pricing Model	The fair value of the warrants was determined using the Black-Scholes option pricing model and the following assumptions: March 31, 2019 Expected term (in years) 5.3 Expected volatility 43.9% Risk-free interest rate 2.5% Expected dividend yield 0%

Cash Equivalents and Short-Te_2

Cash Equivalents and Short-Term Investments (Tables)	3 Months Ended
	Mar. 31, 2020
Cash And Cash Equivalents [Abstract]
Summary of Cash Equivalents and Short-Term Investments	The following is a summary of the Company’s cash equivalents and short-term investments: March 31, 2020 Amortized Cost Basis Unrealized Gains Unrealized Losses Fair Value (in thousands) U.S. Treasury securities $ 36,160 $ 107 $ — $ 36,267 Money market funds 110,893 — — 110,893 Commercial paper 10,968 — — 10,968 Corporate bonds 5,047 — (4 ) 5,043 Total $ 163,068 $ 107 $ (4 ) $ 163,171 Reported as: Cash equivalents $ 115,893 Short-term investments 47,278 Total $ 163,171 December 31, 2019 Amortized Cost Basis Unrealized Gains Unrealized Losses Fair Value (in thousands) U.S. Treasury securities $ 43,219 $ 27 $ (1 ) $ 43,245 Money market funds 29,386 — — 29,386 Reverse repurchase agreements 10,000 — — 10,000 Commercial paper 6,958 — — 6,958 Corporate bonds 8,087 9 — 8,096 Total $ 97,650 $ 36 $ (1 ) $ 97,685 Reported as: Cash equivalents $ 41,381 Short-term investments 56,304 Total $ 97,685

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Inventory	Inventory consists of the following: March 31, December 31, 2020 2019 (in thousands) Raw material $ 2,726 $ 2,501 Work in progress 2,044 1,364 Finished goods 9,532 6,642 Consigned inventory 1,619 1,567 Total inventory $ 15,921 $ 12,074
Schedule of Accrued Liabilities	Accrued liabilities consist of the following: March 31, December 31, 2020 2019 (in thousands) Accrued employee compensation $ 4,835 $ 8,139 Accrued asset purchases 4,377 — Accrued research and development costs 4,100 3,090 Accrued professional services 1,361 804 Other 1,153 1,744 Total accrued liabilities $ 15,826 $ 13,777

Term Notes (Tables)

Term Notes (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long Term Debt	Long-term debt and net discount or premium balances are as follows: March 31, December 31, 2020 2019 (in thousands) Principal amount of term note $ 16,500 $ 13,334 Net (discount) premium associated with accretion of final payment, issuance of common stock warrants, and other debt issuance costs (374 ) 485 Term note, current and noncurrent 16,126 13,819 Less term note, current portion — (6,667 ) Term note, noncurrent portion $ 16,126 $ 7,152
Schedule of Future Minimum Payments for Principal and Interest	Future minimum payments of principal and estimated payments of interest on the Company’s outstanding variable rate borrowings as of March 31, 2020 are as follows: Year ending December 31: (in thousands) 2020 (remainder) $ 441 2021 3,861 2022 6,961 2023 8,294 Total future payments 19,557 Less amounts representing interest (1,489 ) Less final payment (1,568 ) Total principal amount of term note payments $ 16,500

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Total Stock-Based Compensation	Total stock-based compensation was as follows: Three Months March 31, 2020 2019 (in thousands) Cost of product revenue $ 161 $ 27 Research and development 488 72 Sales and marketing 559 108 General and administrative 663 205 Total stock-based compensation $ 1,871 $ 412
Schedule of Estimates Grant-Date Fair Value of Option Awards Using Black-Scholes Option Pricing Model with Assumptions	The Company estimates the grant-date fair value of the Company’s option awards using the Black-Scholes option pricing model. The assumptions for the Black-Scholes model for the three months ended March 31, 2020 and 2019 were as follows: Three Months Ended March 31, 2020 2019 Expected term (in years) 6.08 6.08 Expected volatility 42.4%-42.9% 42.4%-42.9% Risk-free interest rate 2.4%-2.6% 2.5%-2.6% Expected dividend yield 0% 0%
Schedule of Option Activity under 2009 Plan and 2019 Plan	Stock Options Option activity under the 2009 Plan and 2019 Plan is set forth below: Shares Available for Grant Number of Shares Weighted- Average Exercise Price Per Share Weighted- Average Remaining Term Aggregate Intrinsic Value (in years) (in thousands) Balance, December 31, 2019 1,704,244 3,315,001 $ 5.08 7.28 $ 128,774 Awards authorized 943,345 — Options exercised — (356,128 ) 3.12 Options cancelled 13,339 (13,339 ) 3.90 Balance, March 31, 2020 2,660,928 2,945,534 $ 5.33 7.33 $ 82,046 Vested and exercisable, March 31, 2020 1,637,003 $ 3.93 6.76 $ 47,876 Vested and expected to vest, March 31, 2020 2,945,534 $ 5.33 7.33 $ 82,046
Schedule of RSU Activity under 2019 Plan	RSU activity under the 2019 Plan is set forth below : Number of Shares Weighted- Average Grant Date Fair Value Per Share Balance, December 31, 2019 280,904 $ 38.12 RSUs granted 445,205 42.14 RSUs forfeited (3,700 ) 37.19 Balance, March 31, 2020 722,409 $ 40.60

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Summary of Outstanding Potentially Dilutive Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share	The following outstanding potentially dilutive common stock equivalents have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect: March 31, 2020 2019 Common stock options issued and outstanding 2,945,534 3,960,505 Restricted stock units 722,409 5,328 Common stock warrants — 89,343 Total 3,667,943 4,055,176

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Schedule of Product Revenue Based on Location	The following table represents the Company’s product revenue based on the location to which the product is shipped: Three Months Ended March 31, 2020 2019 (in thousands) United States $ 7,769 $ 3,636 Germany 911 643 Rest of Europe 5,108 2,736 All other countries 1,409 254 Product revenue $ 15,197 $ 7,269

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Entity incorporation, date of incorporation	Jun. 17, 2009
Accumulated deficit	$ (196,749)	$ (177,974)
Cash, cash equivalents and short-term investments	$ 170,400

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 123,111	$ 139,045
Restricted cash	1,450	1,450
Total cash, cash equivalents, and restricted cash	$ 124,561	$ 140,495	$ 138,514	$ 40,093

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Notice period for cancellation of agreement	30 days

Financial Instruments and Fai_3

Financial Instruments and Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets:
Total assets	$ 163,171	$ 97,685
U.S. Treasury securities
Assets:
Total assets	36,267	43,245
Money Market Funds
Assets:
Total assets	110,893	29,386
Reverse Repurchase Agreements
Assets:
Total assets		10,000
Commercial paper
Assets:
Total assets	10,968	6,958
Corporate bonds
Assets:
Total assets	5,043	8,096
Level 1
Assets:
Total assets	147,160	72,631
Level 1 | U.S. Treasury securities
Assets:
Total assets	36,267	43,245
Level 1 | Money Market Funds
Assets:
Total assets	110,893	29,386
Level 2
Assets:
Total assets	16,011	25,054
Level 2 | Reverse Repurchase Agreements
Assets:
Total assets		10,000
Level 2 | Commercial paper
Assets:
Total assets	10,968	6,958
Level 2 | Corporate bonds
Assets:
Total assets	$ 5,043	$ 8,096

Financial Instruments and Fai_4

Financial Instruments and Fair Value Measurements - Schedule of Change in the Fair Value of the Warrant Liability (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Fair Value Disclosures [Abstract]
Balance at December 31, 2018	$ 313
Change in fair value of warrant liability	609
Net exercise of warrants	(133)
Conversion of Series A preferred stock warrants to common stock warrants upon the closing of the IPO	$ (789)

Financial Instruments and Fai_5

Financial Instruments and Fair Value Measurements - Fair Value of Warrants Using Black-Scholes Option Pricing Model (Details)	Mar. 31, 2020
Measurement Input, Expected Term
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Expected term (in years)	5 years 3 months 18 days
Measurement Input, Expected Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value assumption measurement input	43.9
Measurement Input, Risk-free Interest Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value assumption measurement input	2.5
Measurement Input, Expected Dividend Yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value assumption measurement input	0

Cash Equivalents and Short-Te_3

Cash Equivalents and Short-Term Investments - Summary of Cash Equivalents and Short-Term Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Cash And Cash Equivalents [Line Items]
Cash equivalents, Fair Value	$ 115,893	$ 41,381
Cash equivalents and short-term investments, Cost Basis	163,068	97,650
Cash equivalents and short-term investments, Unrealized Gains	107	36
Cash equivalents and short-term investments, Unrealized losses	(4)	(1)
Cash equivalents and short-term investments, Fair Value	163,171	97,685
Short-term investments	47,278	56,304
U.S. Treasury securities
Cash And Cash Equivalents [Line Items]
Short-term investments Amortized Cost Basis	36,160	43,219
Short-term investments Unrealized Gains	107	27
Short-term investments Unrealized Losses		(1)
Short-term investments, Fair Value	36,267	43,245
Commercial paper
Cash And Cash Equivalents [Line Items]
Short-term investments Amortized Cost Basis	10,968	6,958
Short-term investments, Fair Value	10,968	6,958
Corporate bonds
Cash And Cash Equivalents [Line Items]
Short-term investments Amortized Cost Basis	5,047	8,087
Short-term investments Unrealized Gains		9
Short-term investments Unrealized Losses	(4)
Short-term investments, Fair Value	5,043	8,096
Reverse Repurchase Agreements
Cash And Cash Equivalents [Line Items]
Short-term investments Amortized Cost Basis		10,000
Short-term investments, Fair Value		10,000
Money Market Funds
Cash And Cash Equivalents [Line Items]
Cash equivalents Amortized Cost Basis	110,893	29,386
Cash equivalents, Fair Value	$ 110,893	$ 29,386

Cash Equivalents and Short-Te_4

Cash Equivalents and Short-Term Investments - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2020
Maximum
Cash And Cash Equivalents [Line Items]
Available for sale securities remaining contractual maturities	1 year

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw material	$ 2,726	$ 2,501
Work in progress	2,044	1,364
Finished goods	9,532	6,642
Consigned inventory	1,619	1,567
Total inventory	$ 15,921	$ 12,074

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued employee compensation	$ 4,835	$ 8,139
Accrued asset purchases	4,377
Accrued research and development costs	4,100	3,090
Accrued professional services	1,361	804
Other	1,153	1,744
Total accrued liabilities	$ 15,826	$ 13,777

Term Notes - Additional Informa

Term Notes - Additional Information (Detail) - USD ($)	Feb. 29, 2020	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Feb. 28, 2018
Debt Instrument [Line Items]
Debt Amount		$ 16,500,000		$ 13,334,000
Debt, final payment amount		1,568,000
Interest expense		$ 277,000	$ 245,000
Loan and Security Agreement
Debt Instrument [Line Items]
Debt, final payment as percentage of original aggregate principal amount		6.75%
Debt, final payment amount		$ 1,600,000					$ 1,000,000
Proceeds of supplemental term loan	$ 4,300,000
Debt payments description		The Amended Credit Facility provides an interest-only payments period through either (a) June 30, 2021, if the Company does not achieve a certain financial performance target on or before June 30, 2021 (“Performance Milestone One”), or (b) December 31, 2021, if the Company achieves Performance Milestone One but does not achieve both of a certain regulatory milestone and a certain financial performance target on or before December 31, 2021 (“Performance Milestone Two”) or (c) until June 30, 2022, if the Company achieves both Performance Milestones.
Interest expense		$ 100,000	100,000
Amortization of debt discount		$ 200,000	$ 100,000
Loan and Security Agreement | Supplemental Term Loan
Debt Instrument [Line Items]
Debt Amount	16,500,000
Debt interest rate		3.50%
Proceeds of supplemental term loan, net of final balloon payment fee	$ 3,300,000
Debt maturity date	Dec. 1, 2023
Loan and Security Agreement | Minimum
Debt Instrument [Line Items]
Debt interest rate		1.75%
Loan and Security Agreement | Minimum | Prime Rate | Supplemental Term Loan
Debt Instrument [Line Items]
Debt interest rate basis	1.25%
Loan and Security Agreement | Maximum
Debt Instrument [Line Items]
Debt interest rate basis		2.75%
Loan and Security Agreement | Maximum | Supplemental Term Loan
Debt Instrument [Line Items]
Debt interest rate	3.50%
Loan and Security Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Termination of line of credit facility	$ 2,000,000
Loan and Security Agreement | Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Line of credit facility termination fee	$ 100,000
Loan and Security Agreement | Silicon Valley Bank
Debt Instrument [Line Items]
Debt, warrants issued		34,440
Debt, fair value of warrants issued		$ 100,000
Loan and Security Agreement | Silicon Valley Bank | Short Term Notes
Debt Instrument [Line Items]
Debt Amount							15,000,000
Loan and Security Agreement | Silicon Valley Bank | Short Term Notes | Tranche One
Debt Instrument [Line Items]
Debt Amount						$ 10,000,000
Loan and Security Agreement | Silicon Valley Bank | Short Term Notes | Tranche Two
Debt Instrument [Line Items]
Debt Amount					$ 5,000,000
Loan and Security Agreement | Silicon Valley Bank | Revolving Credit Facility
Debt Instrument [Line Items]
Debt Amount							$ 2,000,000

Term Note - Long-term Debt and

Term Note - Long-term Debt and Net Premium Balance (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument Periodic Payment [Abstract]
Principal amount of term note	$ 16,500	$ 13,334
Net (discount) premium associated with accretion of final payment, issuance of common stock warrants, and other debt issuance costs	(374)	485
Term note, current and noncurrent	16,126	13,819
Less term note, current portion		(6,667)
Term note, noncurrent portion	$ 16,126	$ 7,152

Term Note - Schedule of Future

Term Note - Schedule of Future Minimum and Estimated Payments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
2020 (remainder)	$ 441
2021	3,861
2022	6,961
2023	8,294
Total future payments	19,557
Less amounts representing interest	(1,489)
Less final payment	(1,568)
Total principal amount of term note payments	$ 16,500	$ 13,334

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Total Stock-Based Compensation (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 1,871	$ 412
Cost of Product Revenue
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	161	27
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	488	72
Sales and Marketing
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	559	108
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 663	$ 205

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Estimates Grant-Date Fair Value of Option Awards Using Black-Scholes Option Pricing Model with Assumptions (Detail)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected term (in years)	6 years 29 days	6 years 29 days
Expected volatility, minimum	42.40%	42.40%
Expected volatility, maximum	42.90%	42.90%
Risk-free interest rate, minimum	2.40%	2.50%
Risk-free interest rate, maximum	2.60%	2.60%
Expected dividend yield	0.00%	0.00%

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended
	Mar. 31, 2019	Feb. 28, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for issuance			2,660,928		1,704,244
Stock-based compensation			$ 1,871,000	$ 412,000
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			4 years
Cliff vesting, percentage			25.00%
Share-based compensation vesting rights, terms			The RSUs generally vest over a four-year period with straight-line vesting and a 25% one year cliff or over a three year period in equal amounts on a semi-annual basis,
2019 Stock Option and Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance		2,000,430
Maximum period of automatic annual increase in common stock reserved for issuance		10 years
Automatic annual increase in common stock reserved for issuance		3.00%
Shares available for issuance			2,660,928
2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	300,650			300,650
Shares available for issuance			590,407
Purchase shares of common stock, price per share, percentage of fair market value	85.00%
Stock-based compensation			$ 191,000

Stock-Based Compensation - Sc_3

Stock-Based Compensation - Schedule of Option Activity under 2009 Plan and 2019 Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Shares Available for Grant
Shares Available for Grant, Beginning balance	1,704,244
Shares Available for Grant, Awards authorized	943,345
Shares Available for Grant, Options cancelled	13,339
Shares Available for Grant, Ending balance	2,660,928	1,704,244
Number of Shares
Number of Shares, Beginning balance	3,315,001
Number of Shares, Options exercised	(356,128)
Number of Shares, Options cancelled	(13,339)
Number of Shares, Ending balance	2,945,534	3,315,001
Number of Shares, Vested and exercisable	1,637,003
Number of Shares, Vested and expected to vest	2,945,534
Weighted-Average Exercise Price Per Share
Weighted-Average Exercise Price Per Share, Beginning balance	$ 5.08
Weighted-Average Exercise Price Per Share, Options exercised	3.12
Weighted-Average Exercise Price Per Share, Options cancelled	3.90
Weighted-Average Exercise Price Per Share, Ending balance	5.33	$ 5.08
Weighted-Average Exercise Price Per Share, Vested and exercisable	3.93
Weighted-Average Exercise Price Per Share, Vested and expected to vest	$ 5.33
Weighted-Average Remaining Term
Weighted-Average Remaining Term, Balance	7 years 3 months 29 days	7 years 3 months 10 days
Weighted-Average Remaining Term, Vested and exercisable	6 years 9 months 3 days
Weighted-Average Remaining Term, Vested and expected to vest	7 years 3 months 29 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Balance	$ 82,046	$ 128,774
Aggregate Intrinsic Value, Vested and exercisable	47,876
Aggregate Intrinsic Value, Vested and expected to vest	$ 82,046

Stock-Based Compensation - Sc_4

Stock-Based Compensation - Schedule of RSU Activity under 2019 Plan (Detail) - Restricted Stock Units	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Number of Shares
Number of Shares, Beginning balance | shares	280,904
Number of Shares, RSUs granted | shares	445,205
Number of Shares, RSUs forfeited | shares	(3,700)
Number of Shares, Ending balance | shares	722,409
Weighted-Average Grant Date Fair Value Per Share
Weighted-Average Grant Date Fair Value Per Share, Beginning balance | $ / shares	$ 38.12
Weighted-Average Grant Date Fair Value Per Share, RSUs granted | $ / shares	42.14
Weighted-Average Grant Date Fair Value Per Share, RSUs forfeited | $ / shares	37.19
Weighted-Average Grant Date Fair Value Per Share, Ending balance | $ / shares	$ 40.60

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Outstanding Potentially Dilutive Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	3,667,943	4,055,176
Common Stock Options Issued and Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	2,945,534	3,960,505
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	722,409	5,328
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share		89,343

Segment and Geographic Inform_3

Segment and Geographic Information - Schedule of Product Revenue Based on Location (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues From External Customers And Long Lived Assets [Line Items]
Product revenue	$ 15,197	$ 7,269
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Product revenue	7,769	3,636
Germany
Revenues From External Customers And Long Lived Assets [Line Items]
Product revenue	911	643
Rest of Europe
Revenues From External Customers And Long Lived Assets [Line Items]
Product revenue	5,108	2,736
All Other Countries
Revenues From External Customers And Long Lived Assets [Line Items]
Product revenue	$ 1,409	$ 254