ViewRay (VRAYQ) 10-K 5 Mar 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 26, 2021	Jun. 30, 2020
Cover [Abstract]
Entity Registrant Name	ViewRay, Inc.
Entity Central Index Key	0001597313
Document Type	10-K
Trading Symbol	VRAY
Document Period End Date	Dec. 31, 2020
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		160,801,302
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Entity Current Reporting Status	Yes
Entity Shell Company	false
ICFR Auditor Attestation Flag	false
Entity File Number	001-37725
Entity Tax Identification Number	42-1777485
Entity Address, Address Line One	2 Thermo Fisher Way
Entity Address, City or Town	Oakwood Village
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	44146
City Area Code	440
Local Phone Number	703-3210
Title of 12(b) Security	Common Stock, par value $0.01
Entity Interactive Data Current	Yes
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Transition Report	false
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Public Float			$ 273,162,523
Documents Incorporated by Reference	Portions of the Registrant’s definitive proxy statement to be delivered to stockholders in connection with the Annual Meeting of Shareholders to be held in 2021 are incorporated by reference in Part III of this Form 10-K where indicated.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 156,720	$ 226,783
Accounts receivable	11,769	16,817
Inventory, net of allowance of $2,286 and $1,363, respectively	46,641	55,031
Deposits on purchased inventory	2,084	6,457
Deferred cost of revenue	1,954	3,466
Prepaid expenses and other current assets	5,257	3,310
Total current assets	224,425	311,864
Property and equipment, net	24,062	23,399
Restricted cash	1,460	1,404
Intangible assets, net	50	55
Right-of-use assets	10,129	11,720
Other assets	1,426	1,577
TOTAL ASSETS	261,552	350,019
Current liabilities:
Accounts payable	9,984	13,739
Accrued liabilities	19,281	21,390
Customer deposits	15,463	9,662
Operating lease liability, current	2,089	2,264
Current portion of long-term debt	0	1,556
Deferred revenue, current portion	10,094	10,457
Total current liabilities	56,911	59,068
Deferred revenue, net of current portion	2,572	3,553
Long-term debt	56,940	53,995
Warrant liability	4,864	5,373
Operating lease liability, noncurrent	9,043	10,479
Other long-term liabilities	956	1,377
TOTAL LIABILITIES	131,286	133,845
Commitments and contingencies (Note 6)	0	0
Stockholders’ equity:
Preferred stock, par value $0.01 per share; 10,000,000 shares authorized at December 31, 2020 and 2019; no shares issued and outstanding at December 31, 2020 and 2019	0	0
Common stock, par value of $0.01 per share; 300,000,000 shares authorized at December 31, 2020 and 2019; 148,615,351 and 147,191,695 shares issued and outstanding at December 31, 2020 and 2019	1,476	1,462
Additional paid-in capital	755,874	733,888
Accumulated deficit	(627,084)	(519,176)
TOTAL STOCKHOLDERS’ EQUITY	130,266	216,174
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 261,552	$ 350,019

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Inventory, allowance	$ 2,286	$ 1,363
Preferred stock, par value per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	148,615,351	147,191,695
Common stock, shares outstanding	148,615,351	147,191,695

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Total revenue	$ 57,017	$ 87,782	$ 80,962
Cost of revenue:
Total cost of revenue	61,076	93,260	74,359
Gross margin	(4,059)	(5,478)	6,603
Operating expenses:
Research and development	25,008	23,794	16,520
Selling and marketing	15,181	25,806	15,062
General and administrative	61,729	65,717	50,113
Total operating expenses	101,918	115,317	81,695
Loss from operations	(105,977)	(120,795)	(75,092)
Interest income	791	1,721	8
Interest expense	(3,307)	(4,327)	(7,701)
Other income (expense), net	585	3,202	6,389
Loss before provision for income taxes	(107,908)	(120,199)	(76,396)
Provision for income taxes	0	0	0
Net loss and comprehensive loss	(107,908)	(120,199)	(76,396)
Amortization of beneficial conversion feature related to Series A convertible preferred stock	0	0	(2,728)
Net loss attributable to common stockholders, basic and diluted	$ (107,908)	$ (120,199)	$ (79,124)
Net loss per share, basic and diluted	$ (0.73)	$ (1.18)	$ (0.98)
Weighted-average common shares used to compute net loss per share attributable to common stockholders, basic and diluted	147,895,561	102,001,954	81,123,140
Product
Revenue:
Total revenue	$ 42,742	$ 79,504	$ 76,626
Cost of revenue:
Total cost of revenue	49,347	80,446	66,522
Service
Revenue:
Total revenue	13,800	7,803	3,861
Cost of revenue:
Total cost of revenue	11,729	12,814	7,837
Distribution Rights
Revenue:
Total revenue	$ 475	$ 475	$ 475

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Public Offering	Direct Registered Offering	At The Market Offering Program	Convertible Preferred StockDirect Registered Offering	Additional Paid-in Capital	Additional Paid-in CapitalPublic Offering	Additional Paid-in CapitalDirect Registered Offering	Additional Paid-in CapitalAt The Market Offering Program	Additional Paid-in CapitalConvertible Preferred StockDirect Registered Offering	Common Stock	Common StockPublic Offering	Common StockDirect Registered Offering	Common StockAt The Market Offering Program	Accumulated Deficit	Accumulated DeficitDirect Registered Offering
Balance at Dec. 31, 2017	$ 1,987					$ 321,174					$ 666				$ (319,853)
Balance, shares at Dec. 31, 2017											67,653,974
Issuance of common stock from option exercises	5,285					5,259					$ 26
Issuance of common stock from option exercises, shares											2,608,812
Issuance of common stock from releases of restricted stock units, shares											59,437
Stock-based compensation	14,169					14,169
Issuance of common stock, value		$ 161,869	$ 30,093	$ 272			$ 161,682	$ 30,052	$ 272			$ 187	$ 41
Issuance of common stock, shares												18,648,649	4,090,000	33,097
Issuance of preferred Series A stock upon direct registered offering, value			22,207		$ 30			2,728		$ 22,177						$ (2,728)
Issuance of preferred Series A stock upon direct registered offering, share					3,000,581
Issuance of common stock warrants in connection with direct registered offering			$ 6,623					6,623
Conversion of Series A preferred stock into common stock, value					$ (30)			$ 22,177		$ (22,177)			$ 30
Conversion of Series A preferred stock into common stock, share					(3,000,581)								3,000,581
Issuance of common stock from warrant exercises	3					1					$ 2
Issuance of common stock from warrant exercises, shares											237,473
Reclassification of warrant liability to additional paid-in capital upon warrant exercises	1,197					1,197
Net loss	(76,396)														(76,396)
Balance at Dec. 31, 2018	167,309					565,334					$ 952				(398,977)
Balance, shares at Dec. 31, 2018											96,332,023
Issuance of common stock from option exercises	9,641					9,618					$ 23
Issuance of common stock from option exercises, shares											2,219,251
Issuance of common stock from releases of restricted stock units						(4)					$ 4
Issuance of common stock from releases of restricted stock units, shares											393,722
Tax withholding paid on behalf of employees for stock-based awards	(2,410)					(2,410)
Stock-based compensation	19,444					19,444
Issuance of common stock, value		138,413					137,935					$ 478
Issuance of common stock, shares												47,782,500
Issuance of common stock from warrant exercises						(5)					$ 5
Issuance of common stock from warrant exercises, shares											464,199
Reclassification of warrant liability to additional paid-in capital upon warrant exercises	3,976					3,976
Net loss	(120,199)														(120,199)
Balance at Dec. 31, 2019	216,174					733,888					$ 1,462				(519,176)
Balance, shares at Dec. 31, 2019											147,191,695
Issuance of common stock from option exercises	$ 15					15
Issuance of common stock from option exercises, shares	20,579										20,579
Issuance of common stock from releases of restricted stock units						(12)					$ 12
Issuance of common stock from releases of restricted stock units, shares											1,214,786
Tax withholding paid on behalf of employees for stock-based awards	$ (1,376)					(1,376)
Stock-based compensation	22,805					22,805
Issuance of common stock from employee stock purchase plan	365					363					$ 2
Issuance of common stock from employee stock purchase plan, shares											188,291
Write-down of offering costs related to previous issuance of common stock upon public offering		$ 191					$ 191
Net loss	(107,908)														(107,908)
Balance at Dec. 31, 2020	$ 130,266					$ 755,874					$ 1,476				$ (627,084)
Balance, shares at Dec. 31, 2020											148,615,351

Consolidated Statements of Co_2

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Direct Registered Offering
Offering cost		$ 177
Public Offering
Offering cost	$ 11,146	10,631
At The Market Offering Program
Offering cost		$ 6

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (107,908)	$ (120,199)	$ (76,396)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	6,419	4,655	3,499
Stock-based compensation	22,805	19,445	14,169
Accretion on asset retirement obligation	63	43	33
Change in fair value of warrant liability	(509)	(2,496)	(9,379)
Loss on disposal of property and equipment	139	3	3
Inventory lower of cost and net realizable value adjustment	150	0	340
Amortization of debt discount and interest accrual	729	703	3,628
Loss on debt extinguishment	0	0	2,416
Product upgrade reserve	(2,294)	3,794	0
Changes in operating assets and liabilities:
Accounts receivable	5,048	20,050	(16,541)
Inventory	8,240	(5,951)	(32,214)
Deposits on purchased inventory	4,373	1,685	(1,099)
Deferred cost of revenue	(186)	1,755	3,500
Prepaid expenses and other assets	(1,356)	2,963	(2,343)
Accounts payable	(3,352)	2,759	(870)
Accrued expenses and other long-term liabilities	(292)	6,995	(9,174)
Customer deposits and deferred revenue	4,457	(15,771)	(1,766)
Net cash used in operating activities	(63,474)	(79,567)	(122,194)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(6,183)	(7,760)	(3,685)
Purchase of intangible and other assets	0	(57)	0
Net cash used in investing activities	(6,183)	(7,817)	(3,685)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from term loan modification	2,000	0	0
Proceeds from draw down of long-term debt, gross	0	0	56,000
Payment of debt issuance costs	(815)	(168)	(468)
Payment of long-term debt	0	0	(45,000)
Payment on debt extinguishment fee	0	0	(172)
Proceeds from employee stock purchase plan	365	0	0
Proceeds from the exercise of stock options	15	9,641	5,285
Proceeds from the exercise of warrants	0	0	3
Payments for taxes related to net share settlement of equity awards	(1,376)	(2,410)	0
Net cash (used in) provided by financing activities	(350)	146,206	236,712
NET (DECREASE) INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(70,007)	58,822	110,833
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — BEGINNING OF PERIOD	228,187	169,365	58,532
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — END OF PERIOD	158,180	228,187	169,365
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	3,262	3,954	11,161
Cash paid for taxes	43	19	0
SUPPLEMENTAL NON-CASH INVESTING AND FINANCING ACTIVITIES:
Fair value of common stock warrants reclassed from liability to additional paid-in capital upon exercise	0	3,975	1,197
Right-of-use assets obtained in exchange for new operating lease liabilities	643	1,647	0
Transfer of property and equipment from inventory	1,698	4,897	2,247
Purchase of property and equipment in accounts payable and accrued expenses	59	657	157
Offering costs included in accounts payable and accrued expenses	460	730	168
Public Offering
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from offering of common stock, gross	0	149,559	172,500
Payment of offering costs related to common stock issuance	(539)	(10,416)	(10,631)
At The Market Offering Program
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from offering of common stock, gross	0	0	278
Payment of offering costs related to common stock issuance	0	0	(6)
Direct Registered Offering
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from offering of common stock, gross	0	0	59,100
Payment of offering costs related to common stock issuance	$ 0	$ 0	$ (177)

Background and Organization

Background and Organization	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Background and Organization	1. Background and Organization ViewRay, Inc., or ViewRay or the Company, and its wholly-owned subsidiary ViewRay Technologies, Inc., designs, manufactures and markets MRIdian, an MR Image-Guided radiation therapy system to simultaneously image and treat cancer patients. Since inception, ViewRay Technologies, Inc. has devoted substantially all of its efforts towards research and development, initial selling and marketing activities, raising capital and the manufacturing, shipment and installation of MRIdian systems. In May 2012, ViewRay Technologies, Inc. was granted clearance from the FDA, to sell MRIdian with Cobalt-60. In November 2013, ViewRay Technologies, Inc. received its first clinical acceptance of a MRIdian with Cobalt-60 at a customer site, and the first patient was treated with that system in January 2014. ViewRay Technologies, Inc. has had the right to affix the CE mark to MRIdian with Cobalt-60 in the European Economic Area since November 2014. In September 2016, the Company received the rights to affix the CE mark to MRIdian Linac, and in February 2017, the Company received 510(k) clearance from the FDA to market MRIdian Linac. The Company’s consolidated financial statements have been prepared on the basis of the Company continuing as a going concern for a reasonable period of time. The Company’s principal sources of liquidity are cash flows from public and private share offerings and available borrowings under its term loan agreement, as well as cash receipts from its sales of MRIdian systems. These have historically been sufficient to meet working capital needs, capital expenditures, and debt service obligations. During the year ended December 31, 2020, the Company incurred a net loss from operations of $107.9 million and used cash in operations of $63.5 million. The Company believes that its existing cash balance of $156.7 million as of December 31, 2020, together with anticipated cash proceeds from sales of MRIdian systems will be sufficient to provide liquidity to fund its operations for at least the next 12 months. In addition to the existing cash and cash from sales of MRIdian, the Company also completed a public share offering on January 4, 2021, in which the Company issued and sold of 11,856,500 shares of the Company’s common stock, which included the full exercise of the underwriters’ option to purchase additional shares, at a price to the public of $4.85 per share. The Company completed the offering on January 7, 2021 and received net proceeds of approximately $53.5 million, after deducting the underwriting discounts and commissions and estimated offering expenses payable by the Company.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The consolidated financial statements have been prepared in conformity with U.S. GAAP, and pursuant to the rules and regulations of the Securities and Exchanges Commission, or SEC. The consolidated financial statements include the accounts of ViewRay, Inc. and its wholly-owned subsidiary, ViewRay Technologies, Inc. All inter-company accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported and disclosed in the consolidated financial statements and accompanying notes. Such estimates include, but are not limited to, allocation of revenue to multiple performance obligations within an arrangement, inventory write-downs to reflect net realizable value, assumptions used in the valuation of stock-based awards and warrant liability, and valuation allowances against deferred tax assets. Actual results could differ from these estimates. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. The Company deposits its cash primarily in checking and money market accounts. The carrying amounts of the Company’s cash equivalents approximate their fair values due to their short maturities. Restricted Cash At December 31, 2020 and 2019, the Company had an aggregate of $1.4 million and $0.9 million, respectively, of outstanding letters of credit related to its operating leases and its contractual obligations with distributors and customers. The letters of credit are collateralized by a restricted cash deposit account, which is presented as part of noncurrent assets on the balance sheets because the Company is not certain when the restriction will be lifted on the collateralized letters of credit. At December 31, 2020 and 2019, no amounts were drawn on the letters of credit. The restricted cash balance as of December 31, 2019 also includes collateral of $0.5 million for credit card accounts. Concentration of Credit Risk, Other Risks and Uncertainties Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. Cash and cash equivalents are deposited in checking and money market accounts with various financial institutions. At times, cash balances may be in excess of the amounts insured by the Federal Deposit Insurance Corporation. Management believes the financial risk associated with these balances is minimal and has not experienced any losses to date. The Company performs periodic credit evaluations of its customers’ financial condition and generally requires deposits from its customers. The Company’s accounts receivable were derived from billings to customers. The Company’s customers representing greater than 10% of accounts receivable or revenue for the periods presented were as follows: Revenue Accounts Receivables Year Ended December 31, December 31, Customers 2020 2019 2018 2020 2019 Customer A 11% 30% Customer B 25% Customer C 10% 20% Customer D 34% Customer E 25% Customer F 15% Customer G 19% Customer H 12% 14% The Company’s future results of operations involve a number of risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, rapid technological change, continued acceptance of MRIdian, competition from substitute products and larger companies, protection of proprietary technology, ability to maintain distributor relationships and dependence on key individuals. Furthermore, new products to be developed by the Company require approval from the FDA or other international regulatory agencies prior to commercial sales. There can be no assurance that the Company’s future products will receive the necessary clearances. The Company relies on a concentrated number of suppliers to manufacture essentially all of the components used in MRIdian. The Company’s suppliers may encounter problems during manufacturing due to a variety of reasons, including failure to comply with applicable regulations, including the FDA’s Quality System Regulation, equipment malfunction and environmental factors, any of which could delay or impede our ability to meet demand. Accounts Receivables and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount, net of any allowance for doubtful accounts, and do not bear interest. The allowance for doubtful accounts, if any, is based on the assessment of the collectability of customer accounts. There was no allowance for doubtful accounts recorded at December 31, 2020 and 2019. Fair Value of Financial Instruments Financial instruments consist of cash and cash equivalents, accounts receivable, restricted cash, prepaid expenses and other current assets, accounts payable, accrued liabilities, warrant liability and long-term debt. Cash equivalents are stated at amortized cost, which approximates fair value at the balance sheet dates, due to the short period of time to maturity. Accounts receivable, prepaid expenses and other current assets, accounts payable, accrued liabilities current portion of long-term debt are stated at their carrying value, which approximates fair value due to the short time to the expected receipt or payment date. The warrant liability is carried at fair value. The carrying amount of the Company’s long-term debt approximates its fair value as the stated interest rate approximates market rates currently available to the Company. Inventory and Deposits on Purchased Inventory Inventory consists of purchased components for assembling MRIdian systems and other direct and indirect costs associated with MRIdian system installation. Inventory is stated at the lower of cost or net realizable value. All inventories expected to be placed in service during the normal operating cycle of the Company for the delivery and assembly of MRIdian systems, including items expected to be on hand for more than one year, are classified as current assets. Excess and obsolete inventories are written down based on historical sales and forecasted demand, as judged by management. The Company reduces the carrying value of its inventory for the difference between cost and net realizable value and records a charge to cost of product revenues. The Company recorded an inventory lower of cost and net realizable value adjustment of $ 0.2 million and $ 0.3 million during the years ended December 31, 2020 and 2018 , respectively. There was no lower of cost and net realizable value adjustment during the year ended December 31, 2019 . The Company records inventory items which have been paid for but not yet received and for which title has not yet transferred to the Company as deposits on purchased inventory. Deposits on purchased inventory are included within current assets as the related inventory items are expected to be received and used in MRIdian systems within the Company’s normal operating cycle. The Company assesses the recoverability of deposits on purchased inventory based on credit assessments of the vendors and their history supplying these assets. At December 31, 2020, the Company did not have any instances whereby deposits for purchased inventory were written off or the purchased inventory was not delivered. Shipping and Handling Costs Shipping and handling costs for product shipments to customers are included in cost of product revenue. Shipping and handling costs incurred for inventory purchases are capitalized in inventory and expensed in cost of product revenue. Property and Equipment Property and equipment are recorded at cost. Depreciation is computed over the estimated useful lives, ranging from two to 15 years, of the related assets using the straight-line method. Acquired software is recorded at cost. Amortization of acquired software generally occurs over three years using the straight-line method. Leasehold improvements are amortized on a straight-line basis over the shorter of the useful life or term of the lease. Demonstration units, which are the Company products used for demonstration purpose for customers and/or potential customers, and generally not intended to be sold, are amortized using the straight-line method. Depreciation and amortization periods for property and equipment are as follows: Property and Equipment Estimated Useful Life Prototype 2 - 10 years Machinery and equipment 3 - 15 years Furniture and fixture 5 - 10 years Software 3 years Leasehold improvements Lesser of estimated useful life or remaining lease term Leases We determine if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use (“ROU”) assets, and operating lease liabilities, current and noncurrent, on our consolidated balance sheets. We currently do not have any finance lease arrangements. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date of the lease in determining the present value of future payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Our lease terms may include an option to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Leases with an initial term of 12 months or less are not recorded on the balance sheet; we recognize lease expense for these leases on a straight-line basis over the lease term. Asset Retirement Obligations In connection with two lease agreements and subsequent amendments, the Company has a legal obligation to remove long-lived assets constructed on the leased properties and to restore the leased properties to their original condition. The Company records the fair value of the asset retirement obligation in the period in which it is incurred. The fair value is measured based upon the present value of the expected future payments at inception and remeasured upon the extension of the respective lease agreement. The liability is accreted to its present value each period and the capitalized cost is depreciated over the remaining lease term. Accretion expense is calculated by applying the effective interest rate to the carrying amount of the liability at the beginning of each period. The effective interest rate is the credit-adjusted risk-free rate applied when the liability was initially measured at inception and remeasured upon the lease extension, when applicable. At December 31, 2020, the Company had outstanding asset retirement obligations of $0.9 million, which was included in other long-term liabilities in the accompanying consolidated balance sheets. For the years ended December 31, 2020, 2019 and 2018, the Company recognized accretion expenses of $63 thousand, $43 thousand and $33 thousand in the accompanying statements of operations and comprehensive loss. Impairment of Long-Lived Assets The Company reviews the recoverability of long-lived assets, including equipment, leasehold improvements, software and intangible assets when events or changes in circumstances occur that indicate that the carrying value of the asset may not be recoverable. The assessment of possible impairment is based on the ability to recover the carrying value of the assets from the expected future cash flows (undiscounted and without interest charge) of the related operations. If these cash flows are less than the carrying value of such assets, an impairment loss for the difference between the estimated fair value and carrying value is recorded. There was no impairment loss recognized during the years ended December 31, 2020 , 2019 and 2018 . Revenue Recognition The Company derives revenues primarily from the sale of MRIdian systems and related services as well as support and maintenance services on sold systems. The Company accounts for revenue contracts with customers by applying the requirements of ASC 606, Revenues from Contracts with Customers, • identification of the contract, or contracts, with a customer; • identification of the performance obligations in the contract • determination of the transaction price; • allocation of the transaction price to the performance obligations in the contract; and • recognition of revenue when, or as, the Company satisfies a performance obligation. In all sales arrangements, revenues are recognized when control of the promised goods or services are transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to receive in exchange for those goods or services. For sales of MRIdian systems, beginning in the second quarter of 2019, the Company determined that the MRIdian system and installation of the MRIdian system, which had previously been one performance obligation, are now two performance obligations as they are capable of being distinct and are distinct within the context of the system contracts. This change occurred due primarily to changes in facts and circumstances, whereby there are now readily available resources outside the Company that can perform the system installations. For sales of the related support and maintenance services, a time-elapsed method is used to measure progress toward complete satisfaction of performance obligations and service revenue is recognized ratably over the service contract term, which is typically 12 months. Additional details regarding revenue recognition are included in Note 7 – Revenue . Research and Development Costs Expenditures, including payroll, contractor expenses and supplies, for research and development of products and manufacturing processes are expensed as incurred. Costs for the development of new software products and substantial enhancements to existing software products are expensed as incurred until technological feasibility has been established, at which time any additional costs would be capitalized. No costs associated with the development of software have been capitalized as the Company believes its current software development process is completed concurrent with the establishment of technological feasibility. Stock-Based Compensation Stock-based compensation expense for all share-based payment awards granted is based on the grant date fair value. The Company uses the Black-Scholes option-pricing model to estimate the fair value of stock options. The Black-Scholes option-pricing model requires the use of highly subjective assumptions, including the options’ expected term and the price volatility of the underlying stock Deferred Commissions Deferred commissions are the direct and incremental costs directly associated with the MRIdian system contracts with customers, which primarily consist of sales commissions to our direct sales force. The commissions are deferred and expensed in proportion to the revenue recognized upon the acceptance of the MRIdian system. At December 31, 2020 and 2019, the Company had $2.4 million and $2.1 million, respectively, in deferred commissions recorded as part of prepaid expenses and other current assets on the consolidated balance sheets. Income Taxes The Company uses the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Deferred tax expense or benefit is the result of changes in the deferred tax assets and liabilities. Valuation allowances are established when necessary to reduce deferred tax assets where, based upon the available evidence, management concludes that it is more-likely-than not that the deferred tax assets will not be realized. Because of the uncertainty of the realization of the deferred tax assets, the Company has recorded a full valuation allowance against its net deferred tax assets. In evaluating the ability to recover its deferred income tax assets, the Company considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction-by-jurisdiction basis. In the event the Company was to determine that it would be able to realize its deferred income tax assets in the future in excess of their net recorded amount, it would make an adjustment to the valuation allowance which would reduce the provision for income taxes. Reserves are provided for tax benefits for which realization is uncertain. Such benefits are only recognized when the underlying tax position is considered more likely than not to be sustained on examination by a taxing authority, assuming they possess full knowledge of the position and facts. It is the Company’s policy to include any penalties and interest related to income taxes in its income tax provision; however, the Company currently has no penalties or interest related to income taxes. The earliest year that the Company is subject to examination is the year ended December 31, 2004. Warrant Liability Certain warrants to purchase common stock provide for cash settlement in the event of a change in control, and are recorded as liabilities on the balance sheets at fair value upon issuance (see Note 12). These warrants are subject to re-measurement to fair value at each balance sheet date. Any changes in fair value are recognized in the consolidated statements of operations and comprehensive loss as other income (expense), net. Upon exercise of the warrants, the related warrant liability will be reclassified to additional paid-in capital. Net Loss per Share The Company’s basic net loss attributable to common stockholders per share is calculated by dividing net loss by the weighted-average number of shares of common stock outstanding for the period. Contingently issuable shares are included in the computation of basic net loss per share as of the date that all necessary conditions have been satisfied and issuance of the shares is no longer contingent. The diluted net loss per share is computed by giving effect to all potential common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, stock options, restricted stock units and warrants to purchase common stock are considered to be common stock equivalents but have been excluded from the calculation of diluted net loss per share as their effect is anti-dilutive. Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, Financial Instruments – Credit Losses In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, In March 2020, the FASB issued ASU 2020-04, Facilitation of the Effects of Reference Rate Reform on Financial Reporting In August 2020, the FASB issued ASU 2020-06, an update to Accounting Standard Codification (“ASC”) Topic 470, Subtopic – 20, Debt – Debt with Conversion and Other Options, and ASC Topic 815, Subtopic – 40, Derivatives and Hedging – Contracts in Entity's Own Equity. The ASU simplifies the guidance for certain financial instruments with characteristics of liability and equity, including convertible instruments and contracts on an entity’s own equity by reducing the number of accounting models for convertible instruments and amends guidance in ASC Topic 260, Earnings Per Share, relating to the computation of earnings per share for convertible instruments and contracts on an entity’s own equity. The ASU is effective for interim and annual reporting periods in fiscal years that begin after December 15, 2021, with early adoption permitted for fiscal years that begin after December 15, 2020. The Company is currently evaluating the impact this guidance may have on its consolidated financial statements and related disclosures. Recently Adopted Accounting Pronouncements Effective January 1, 2020

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	3. Balance Sheet Components Property and Equipment, Net Property and equipment consisted of the following (in thousands): December 31, 2020 2019 Prototype $ 17,711 $ 16,419 Machine and equipment 17,486 15,816 Leasehold improvements 14,196 6,718 Furniture and fixtures 1,295 1,284 Software 1,389 1,389 Construction in progress 486 4,176 Property and equipment, gross 52,563 45,802 Less: accumulated depreciation and amortization (28,501 ) (22,403 ) Property and equipment, net $ 24,062 $ 23,399 Depreciation and amortization expense related to property and equipment was $6.4 million, $4.7 million and $3.4 million during the years ended December 31, 2020, 2019 and 2018, respectively. Accrued Liabilities Accrued liabilities consisted of the following (in thousands): December 31, 2020 2019 Accrued payroll and related benefits $ 12,810 $ 9,577 Accrued accounts payable 2,810 4,764 Payroll withholding tax, sales and other tax payable 1,398 1,066 Accrued legal and accounting 305 1,175 Product upgrade reserve 1,500 3,794 Other 458 1,014 Total accrued liabilities $ 19,281 $ 21,390 Deferred Revenue Deferred revenue consisted of the following (in thousands): December 31, 2020 2019 Deferred revenue: Product $ 1,888 $ 3,141 Services 8,857 8,473 Distribution rights 1,921 2,396 Total deferred revenue 12,666 14,010 Less: current portion of deferred revenue (10,094 ) (10,457 ) Noncurrent portion of deferred revenue $ 2,572 $ 3,553 Other Long-Term Liabilities Other long-term liabilities consisted of the following (in thousands): December 31, 2020 2019 Accrued interest, noncurrent portion $ 99 $ 516 Asset retirement obligation 857 861 Total other-long term liabilities $ 956 $ 1,377

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	4. Fair Value of Financial Instruments Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, as follows: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices 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 assets or liabilities. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The assets’ or liabilities’ fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company’s financial instruments that are carried at fair value mainly consist of Level 3 liabilities. These liabilities that are measured on a recurring basis relate to the 2017 and 2016 Placement Warrants, as described in Note 12. Placement warrant liabilities The gains and losses from re-measurement of Level 3 financial liabilities are recorded as part of other income (expense), net in the consolidated statements of operations and comprehensive loss. During the year ended December 31, 2020, 2019 and 2018, the Company recorded a gain of $0.5 million, $2.5 million, and $9.4 million, respectively, related to the change in fair value of the 2017 and 2016 Placement Warrants. There have been no transfers between Level 1, Level 2 and Level 3 in any periods presented. The following table sets forth the fair value of the Company’s financial liabilities by level within the fair value hierarchy (in thousands): At December 31, 2020 Level 1 Level 2 Level 3 Total 2017 Placement Warrants Liability $ — $ — $ 3,675 $ 3,675 2016 Placement Warrants Liability — — 1,189 1,189 Total Warrant Liability $ — $ — $ 4,864 $ 4,864 At December 31, 2019 Level 1 Level 2 Level 3 Total 2017 Placement Warrants Liability $ — $ — $ 4,043 $ 4,043 2016 Placement Warrants Liability — — 1,330 1,330 Total Warrant Liability $ — $ — $ 5,373 $ 5,373 The following table summarizes the changes in the fair value of the Company’s Level 3 financial liabilities (in thousands): Year Ended December 31, 2020 2019 2018 Fair value, beginning of period $ 5,373 $ 11,844 $ 22,420 Change in fair value of Level 3 financial liabilities (509 ) (2,496 ) (9,379 ) Fair value of 2016 Placement Warrants at exercise — (3,457 ) (1,187 ) Fair value of 2017 Placement Warrants at exercise — (518 ) (10 ) Fair value, end of period $ 4,864 $ 5,373 $ 11,844

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Instruments [Abstract]
Debt	5. Debt SVB Term Loan In December 2018, the Company entered into a term loan agreement, or the SVB Term Loan, with Silicon Valley Bank, for a principal amount of $56.0 million. The SVB Term Loan has a maturity date of December 1, 2023 and bears interest at a rate of 6.30% per annum to be paid monthly over the term of the loan. Beginning on December 1, 2020 (or June 1, 2021, if the Company achieves a trailing twelve-month revenue of at least a specified amount and elects to apply such later date), the Company would have made thirty-six equal monthly payments of principal (or thirty equal payments, if the Company so elects). In addition, upon repayment of the SVB Term Loan in full, the Company will make a final payment equal to 3.15% of the original aggregate principal amount of the SVB Term Loan. The Company used the proceeds of the SVB Term Loan and cash on hand to repay in full its outstanding obligations under the then outstanding CRG Term Loan and to pay fees and expenses related thereto. The Company accounted for the termination of the CRG Term Loan as a debt extinguishment and recorded a debt extinguishment loss of $2.4 million from the difference between the net carrying amount of debt and the amount paid. The debt extinguishment loss includes $0.3 million in write-off of unamortized debt discount and debt issuance costs associated with the CRG Term Loan. The Company received net proceeds of $55.4 million after related legal and consulting fees totaling $0.6 million. Such fees are accounted for as debt discount and issuance costs and presented as a direct deduction from the carrying amount of debt on the Company’s consolidated balance sheets. Debt discount, issuance costs and the final payment are amortized or accreted as interest expense over the term of the loan using the effective interest method. On December 31, 2019, we entered into the First Amendment (the First Amendment) to the SVB Term Loan by and among the Company, ViewRay Technologies, Inc. and SVB dated as of December 28, 2018. The First Amendment, among other things, amended the SVB Term Loan to (i) suspend testing of the minimum revenue financial covenant for the fiscal quarter ending December 31, 2019, (ii) provide for the minimum trailing twelve-month revenue thresholds under the minimum revenue financial covenant for periods ending on the last day of fiscal quarters in fiscal years subsequent to 2020 to be determined annually at the greater of (a) a 25% cushion to revenue forecasts provided by the Company to SVB and (b) 10% year-over-year annual growth, unless otherwise agreed, (iii) increase the minimum liquidity ratio financial covenant from 1.50:1.00 to 1.75:1.00 and (iv) increase the prepayment premium from 1.00% to 2.00% for amounts prepaid under the SVB Term Loan for prior to the maturity date thereof, subject to certain exceptions. On October 30, 2020, the Company entered into the Second Amendment (the Second Amendment) to the SVB Term Loan. The Second Amendment, among other things, amended the SVB Term Loan to (i) increase the term loan agreement principal amount from $56.0 million to $58.0 million, (ii) revise the thirty-six equal monthly payments of principal to begin on November 1, 2022, (iii) revise the maturity date to October 1, 2025, (iv) decrease the interest rate from a fixed rate of 6.3% to a floating rate of 2.4% above the Prime Rate, (v) increase the final payment from 3.15% of the original aggregate principal amount to 3.7% of the revised aggregate principal amount, (vi) revise the minimum trailing twelve-month The SVB Term Loan is secured by substantially all assets of the Company, except that the collateral does not include any intellectual property held by the Company, provided, however, the collateral does include all accounts and proceeds of such intellectual property. The SVB Term Loan contains customary representations and warranties and customary affirmative and negative covenants applicable to the Company and its subsidiaries, including, among other things, restrictions on indebtedness, liens, investments, mergers, dispositions, prepayment of other indebtedness, dividends and other distributions and transactions with affiliates. The SVB Term Loan also contains financial covenants that require the Company to maintain a minimum cash balance in accounts maintained at Silicon Valley Bank or one of its affiliates or else comply with a liquidity ratio and/or a minimum revenue target. The SVB Term Loan includes standard events of default, including, among other things, subject in certain cases to customary grace periods, thresholds and notice requirements, the Company’s failure to fulfill its obligations under the SVB Term Loan or the occurrence of a material adverse change in the Company's business, operations, or condition (financial or otherwise). In the event of default by the Company under the SVB Term Loan, Silicon Valley Bank would be entitled to exercise its remedies thereunder, including the right to accelerate the debt, upon which the Company may be required to repay all amounts then outstanding under the SVB Loan, which could harm the Company's financial condition. The Company’s scheduled future payments on the SVB Term Loan at December 31, 2020 are as follows (in thousands): Year Ended December 31, 2021 $ — 2022 3,222 2023 19,333 2024 19,333 2025 16,112 Total future principal payments 58,000 Less: unamortized debt discount (1,060 ) Carrying value of long-term debt 56,940 Less: current portion — Long-term portion $ 56,940

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Leases The Company leases office space in Oakwood Village, Ohio, Mountain View, California, and Denver, Colorado under noncancelable operating lease agreements. The Company leases and occupies approximately 19,800 square feet of office space in Oakwood Village, Ohio, which expires in October 2026. The Company entered into an office lease agreement to lease approximately 25,500 square feet of office space located in Mountain View, California, with an expiration date of July 2025. In April 2018, the Company entered into a lease agreement to lease additional office space in Mountain View, California of approximately 24,600 square feet, which will expire in December 2025. The Company has the option to extend the term of the lease for a period of up to five years. T In recognition of the right-of-use assets and the related lease liabilities, the option to extend the lease term have not been included as the Company is not reasonably certain that it will exercise any such option. At December 31, 2020, the weighted-average remaining lease term in years is 4.7 years and the weighted-average discount rate used is 7.7%. The Company recognized of $3.1 million and $2.9 million lease costs arising from lease transactions for the years During the years ended December 31, 2020 and 2019, the Company recognized the following cash flow transactions arising from lease transactions (in thousands): For the Year Ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities $ 3,145 $ 2,451 Right-of-use assets obtained in exchange for new operating lease liabilities 643 1,647 At December 31, 2020, the future payments and interest expense for the operating leases are as follows (in thousands): Year Ended December 31, Future Payments 2021 $ 2,847 2022 2,659 2023 2,738 2024 2,774 2025 2,096 Thereafter 147 Total undiscounted cash flows $ 13,261 Less: imputed interest (2,129 ) Present value of lease liabilities $ 11,132 Rent expense for operating leases for the year ended December 31, 2018 using the accounting guidance in effect at that time was $1.4 million. Legal Proceedings In the normal course of business, the Company may become involved in legal proceedings. The Company will accrue a liability for legal proceedings when it is probable that a liability has been incurred and the amount can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. When only a range of possible loss can be established, the most probable amount in the range is accrued. If no amount within this range is a better estimate than any other amount within the range, the minimum amount in the range is accrued. Patent Litigation On September 10, 2019, a complaint for patent infringement was filed by Varian Medical Systems, Inc., in U.S. District Court for the Northern District of California against the Company. Captioned Varian Medical Systems, Inc., v. ViewRay, Inc., the complaint alleges that the Company infringes two related patents, U.S. Patent Nos. 8,637,841 and 9,082,520 and seeks injunctive relief and monetary damages. The Company filed its answer on November 1, 2019. We believe the allegations in the complaint are without merit and have been vigorously defending the litigation. On July 7, 2020 and July 31, 2020, the Company filed petitions with the Patent Trial & Appeal Board of the United States Patent and Trademark Office (PTAB), requesting institution of inter partes review (IPR) and cancellation of claims 1-3, 5-8, 10, 13, 14 of Varian’s U.S. Patent No. 9,082,520. On August 13, 2020, the Company filed a separate petition with the PTAB, requesting an IPR and cancellation of claims 1-4 and 20-22 of Varian’s U.S. Patent No. 8,637,841. In August 2020, Varian announced that it has entered into a definitive agreement to combine with Siemens Healthineers AG. That deal has been approved by Varian’s board of directors, its shareholders, and has passed regulatory review by US government authorities. The merger is expected to close in the first half of 2021, at which time Siemens has agreed to dismiss Varian’s lawsuit and release ViewRay from all claims brought by Varian. In light of this, both the district court case and the proceedings before the PTAB are currently stayed, pending confirmation of the Siemens/Varian merger. Class Action Litigation On September 13, 2019, a class action complaint for violation of federal securities laws was filed in U.S. District Court for the Northern District of Ohio against the Company, its chief executive officer, chief scientific officer, and former chief financial officer. On December 19, 2019, the court appointed Plymouth County Retirement Association as the lead plaintiff, and on February 28, 2020 the lead plaintiff filed an amended complaint asserting securities fraud claims against the Company, its chief executive officer, chief operating officer, chief scientific officer, and former chief executive officer and former chief financial officer. Now captioned Plymouth County Retirement Association v. ViewRay, Inc., et al., the amended complaint alleges that the Company violated federal securities laws by issuing materially false and misleading statements that failed to disclose adverse facts concerning its business, operations, and financial results, and seeks damages, interest, and other relief. The Company filed a motion to dismiss the amended complaint on May 28, 2020. While the initial motion to dismiss was pending, the plaintiff was granted leave to file a second amended complaint. A motion to dismiss the second amended complaint was filed on September 16, 2020. That motion has been fully briefed, and is pending before the District Court. The Company believes the allegations in the complaint are without merit and intend to vigorously defend the litigation. Stockholder Derivative Lawsuit On July 22, 2020, a stockholder derivative lawsuit was filed against ViewRay (as a nominal defendant) and certain of its current and former officers and directors in the U.S. District Court for the Northern District of Ohio. This action alleges, purportedly on behalf of ViewRay, that the officers and directors violated Section 14(a) of the Securities Exchange Act of 1934, breached their fiduciary duties, wasted corporate assets, and were unjustly enriched based on factual assertions substantially similar to those in the class action complaint described above. The complaint seeks, among other things, damages awarded to ViewRay, restitution and disgorgement of profits in an unspecified amount, and corporate reforms. Due to the overlap between the allegations in the derivative complaint and those in the putative securities class action complaint, this lawsuit is stayed until March 3, 2021, pending a decision on the motion to dismiss the second amended complaint in the securities action. Given the early stage of each of the litigation matters described above, at this time the Company is unable to reasonably estimate possible losses or form a judgment that an unfavorable outcome is either probable or remote. However, litigation is subject to inherent uncertainties, and one or more unfavorable outcomes in any claim or litigation against the Company could have a material adverse effect in the period in which they are resolved and on the Company’s business generally. In addition, regardless of their merits or their ultimate outcomes, lawsuits and legal proceedings are costly, divert management attention and may materially adversely affect the Company’s reputation, even if resolved in the Company’s favor. Purchase Commitments At December 31, 2020, the Company had $2.3 million in outstanding firm purchase commitments.

Revenue

Revenue	12 Months Ended
	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Revenue	7. Revenue The Company derives revenue primarily from the sale of MRIdian systems and related services as well as support and maintenance services on sold systems. Revenue is categorized as product revenue, service revenue and distribution rights revenue. The following table presents revenue disaggregated by type and geography (in thousands): Years Ended December 31, U.S. 2020 2019 2018 Product $ 8,428 $ 41,985 $ 32,265 Service 7,739 4,251 1,966 Total U.S. revenue $ 16,167 $ 46,236 $ 34,231 Outside of U.S. ("OUS") Product $ 34,314 $ 37,519 $ 44,361 Service 6,061 3,552 1,895 Distribution rights 475 475 475 Total OUS revenue $ 40,850 $ 41,546 $ 46,731 Total Product $ 42,742 $ 79,504 $ 76,626 Service 13,800 7,803 3,861 Distribution rights 475 475 475 Total revenue $ 57,017 $ 87,782 $ 80,962 Arrangements with Multiple Performance Obligations The Company frequently enters into sales arrangements that include multiple performance obligations. Such performance obligations mainly consist of (i) sale of MRIdian systems, which generally includes installation and embedded software, and (ii) product support, which includes extended service and maintenance. For such arrangements, the Company allocates revenue to each performance obligation based on its relative standalone selling price. The standalone selling price, or SSP, is determined based on observable prices at which the Company separately sells the products and services. If a SSP is not directly observable, the Company will estimate the SSP considering market conditions or internally approved pricing guidelines related to the performance obligations. Product Revenue Product revenue is derived primarily from the sales of MRIdian system. The system contains both software and non-software components that together deliver essential functionality. Certain revenue contracts have terms that result in the control of the system transferring to the customer upon delivery and inspection, as opposed to historically upon customer acceptance. For contracts in which control of the system transfers upon delivery and inspection, the Company recognizes revenue for the systems at the point in time when delivery and inspection by the customer has occurred. For these same contracts, the Company recognizes installation revenue over the period of installation as the installation services are performed and control is transferred to the customer. For all contracts in which control continues to transfer upon post-implementation customer acceptance, revenue for the system and installation will continue to be recognized upon customer acceptance. Certain customer contracts with distributors do not require ViewRay installation at the ultimate user site, and the distributors may either perform the installation themselves or hire another party to perform the installation. For sales of MRIdian systems for which the Company is not responsible for installation, revenue recognition occurs when the entire system is shipped, which is when the control of the system is transferred to the customer. Service Revenue Service revenue is derived primarily from maintenance services. The maintenance and support service is a stand-ready obligation which is performed over the term of the arrangement and, as a result, service revenue is recognized ratably over the service period as the customers benefit from the service throughout the service period. Distribution Rights Revenue In December 2014, the Company entered into a distribution agreement with Itochu Corporation pursuant to which it appointed Itochu as its exclusive distributor for the promotion, sale and delivery of MRIdian products within Japan. In consideration of the exclusive distribution rights granted, the Company received $4.0 million, which was recorded as deferred revenue. Starting in August 2016, distribution rights revenue is recognized ratably over the remaining term of the distribution agreement of approximately 8.5 years. A time-elapsed method is used to measure progress because the control is transferred evenly over the remaining contractual period. Contract Balances The timing of revenue recognition, billings and cash collections results in short-term and long-term trade receivables, customer deposits, deferred revenues and deferred cost of revenue on the consolidated balance sheets. Trade receivables are recorded at the original invoiced amount, net of an estimated allowance for doubtful accounts. Trade credit is generally extended on a short-term basis. The Company occasionally provides for long-term trade credit for its maintenance services so that the period between when the services are rendered to its customers and when the customers pay for that service is within one year. Thus, the Company’s trade receivables do not bear interest or contain a significant financing component. Long-term trade receivables of $0.1 million and $0.2 million were reported within other assets in the consolidated balance sheets at December 31, 2020 and 2019, respectively. These amounts are billed in accordance with the terms of the customer contracts to which they relate and are expected to be collected three to four years from the date of invoice as the underlying maintenance services are rendered. At times, billing occurs subsequent to revenue recognition, resulting in an unbilled receivable which represents a contract asset. This contract asset is recorded as an unbilled receivable and reported as part of accounts receivable on the consolidated balance sheets. Trade receivables are periodically evaluated for collectability based on past credit history of the respective customers and their current financial condition. Changes in the estimated collectability of trade receivables are included in the results of operations for the period in which the estimate is revised. Trade receivables that are deemed uncollectible are offset against the allowance for doubtful accounts. The Company generally does not require collateral for trade receivables. There were no allowances for doubtful accounts recorded at December 31, 2020 or 2019. Customer deposits represent payments received in advance of system installation. For domestic and international sales, advance payments received prior to inventory shipments are recorded as customer deposits. Advance payments are subsequently reclassified to deferred revenue upon inventory shipment. All customer deposits, including those that are expected to be a deposit for more than one year, are classified as current liabilities based on consideration of the Company’s normal operating cycle (the time between acquisition of the inventory components and the final cash collection from customers on these inventory components) which is in excess of one year. Deferred revenue consists of deferred product revenue and deferred service revenue. Deferred product revenue arises from timing differences between the fulfillment of contract obligations and satisfaction of all revenue recognition criteria consistent with the Company’s revenue recognition policy. Deferred service revenue results from the advance billing for services to be delivered over a period of time. Deferred revenues expected to be realized within one year or normal operating cycle are classified as current liabilities. Deferred cost of revenue consists of cost for inventory items that have been shipped, but revenue recognition has not yet occurred. Deferred cost of revenue is included as part of current assets as the corresponding deferred product revenue is expected to be realized within one year or the Company’s normal operating cycle. During the years ended December 31, 2020, 2019 and 2018, the Company recognized $8.3 million, $10.9 million and $19.9 million, respectively, of revenues that were included in the deferred revenue balance at the beginning of each reporting period. Variable Consideration The Company records revenue from customers in an amount that reflects the transaction price it expects to be entitled to after transferring control of those goods or services. The Company estimates the transaction price at contract inception, including any variable consideration, and updates the estimate each reporting period for any changes. For the year ended December 31, 2019, the Company recognized $0.9 million in revenue from performance obligations satisfied in a prior period. The cumulative catch-up adjustment resulted from a change in transaction price related to variable consideration that was constrained in prior periods.

Licensing Agreement

Licensing Agreement	12 Months Ended
	Dec. 31, 2020
Licensing Agreement [Abstract]
Licensing Agreement	8 . Licensing Agreement In December 2004, ViewRay Technologies, Inc. entered into a licensing agreement with the University of Florida Research Foundation, Inc., or UFRF, whereby UFRF granted the Company a worldwide exclusive license to certain of UFRF’s patents in exchange for 33,652 shares of common stock and a royalty from sales of products developed and sold by the Company utilizing the licensed patents. ViewRay Technologies, Inc. met all of the product development and commercialization milestones at December 31, 2013, and started to make quarterly royalty payments in 2014. Royalty payments are based on 1% of net sales, defined as the amount collected on sales of licensed products and/or licensed processes after deducting trade and/or quantity discounts, credits on returns and allowances, outbound transportation costs paid and sales tax. Minimum quarterly royalty payments of $50 thousand commenced with the quarter ended March 31, 2014, and are payable in advance. Minimum royalties paid in any calendar year are credited against earned royalties for such calendar year. The royalty payments continue until the earlier of (i) the date that no licensed patents remain enforceable or (ii) once the payment of earned royalties cease for more than four consecutive calendar quarters. Royalty expenses based on 1% of net sales were $0.7 million, $1.0 million and $0.6 million during the years ended December 31, 2020, 2019 and 2018, respectively, and were recorded as product cost of revenue in the consolidated statements of operations and comprehensive loss. There were no minimum royalty payments in excess of 1% of net sales during the years ended December 31, 2020 and 2019. The minimum royalty payments in excess of 1% of net sales were $30 thousand during the year ended December 31, 2018, and were recorded as general and administrative expenses in the consolidated statements of operations and comprehensive loss.

Distribution Agreement

Distribution Agreement	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Distribution Agreement	9 . Distribution Agreement In December 2014, the Company entered into a distribution agreement with Itochu Corporation, or Itochu, a Japanese entity, pursuant to which the Company appointed Itochu as its exclusive distributor for the sale and delivery of its MRIdian products within Japan. The exclusive distribution agreement has an initial term of 10 years from December 2014, and contains features customary in such distribution agreements. Under this distribution agreement, the Company will supply its products and services to Itochu based upon the Company’s then-current pricing. In consideration of the exclusive distribution rights granted, Itochu agreed to pay a distribution fee of $4.0 million in three installments: (i) the first installment of $1.0 million was due upon execution of the distribution agreement; (ii) the second installment of $1.0 million was due within 10 business days following submission of the application for regulatory approval of the Company’s product to the Japan regulatory authority; and (iii) the final installment of $2.0 million was due within 10 business days following receipt of approval for the Company’s product from the Japanese Ministry of Health, Labor and Welfare. The first and second installments of $2.0 million in aggregate were received in December 2014 and December 2015, respectively. In August 2016, the Company received the third and final $2.0 million installment upon the receipt of regulatory approval to market MRIdian in Japan

Equity Financing

Equity Financing	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Equity Financing	10 . Equity Financing Public Offering of Common Stock On August 14, 2018, the Company entered into an underwriting agreement with Morgan Stanley & Co. LLC and Jefferies LLC, as representatives of several underwriters, or the August 2018 Underwriters, in connection with the issuance and sale of 16,216,217 shares of the Company’s common stock at a public offering price of $9.25 per share. In addition, the Company granted the August 2018 Underwriters a 30-day option to purchase up to 2,432,432 additional shares of common stock on the same terms, which the August 2018 Underwriters exercised in full. The Company completed the offering on August 17, 2018 and received aggregate net proceeds of approximately $161.9 million, after deducting underwriting discounts and commissions and offering expenses payable by the Company. On December 3, 2019 full. The Company completed the offering on December 6, 2019 and received aggregate net proceeds of approximately $ 138.4 million, after deducting underwriting discounts and commissions and offering expenses payable by the Company. Subsequent to year end, on January 4, 2021, the Company entered into an underwriting agreement with Piper Sandler & Co., as representative of the several underwriters named therein (the “2021 Underwriters”), with respect to the issuance and sale of 11,856,500 shares of our common stock, which included the full exercise of the 2021 Underwriters’ option to purchase additional shares, at a price to the public of $4.85 per share. The Company completed the offering on January 7, 2021 and received net proceeds of approximately $53.5 million, after deducting the underwriting discounts and commissions and estimated offering expenses payable by the Company. Direct Registered Offerings In February 2018, the Company entered into a securities purchase agreement pursuant to which it sold (i) 4,090,000 shares of its common stock; (ii) 3,000,581 shares of its Series A convertible preferred stock and (iii) warrants to purchase 1,418,116 shares of its common stock, or the 2018 Offering Warrants, for total gross proceeds of $59.1 million, or the March 2018 Direct Registered Offering. The March 2018 Direct Registered Offering was closed on March 5, 2018. The 2018 Offering Warrants have an exercise price of $8.31 per share, became exercisable upon issuance and expire in March 2025. All outstanding shares of Series A convertible preferred stock were converted into common stock at a conversion ratio of 1:1 on April 19, 2018. At-The-Market Offering of Common Stock In January and April 2017, the Company agreed to sell up to a cumulative $50.0 million of its common stock in accordance with the terms of a sales agreement with FBR Capital Markets & Co., or FBR, pursuant to an at-the-market offering program in accordance with Rule 415(a)(4) under the Securities Act under its then effective shelf registration statement. The Company sold an aggregate of 33,097 shares of its common stock at an average market price of $8.41 per share, resulting in aggregate gross proceeds of approximately $0.3 million, for the year ended December 31, 2018 under the at-the-market offering program. In January 2019, the Company filed a registration statement with the SEC which covers the offering, issuance and sale of up to a maximum aggregate offering price of $250.0 million of our common stock, preferred stock, debt securities, warrants, purchase contracts and/or units, including up to $100.0 million of the Company’s common shares pursuant to an at-the-market offering program with FBR, now known as B. Riley Securities. Under this at-the-market offering program, the Company did not sell any shares of its common stock during the years ended December 31, 2019 or December 31, 2020. The consummation of the January 2021 public offering of common stock effectively reduced the common shares available for issuance under the at-the-market offering program to approximately $42.9 million.

Convertible Preferred Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Convertible Preferred Stock	1 1 . Convertible Preferred Stock In March 2018, the Company issued 3,000,581 shares of Series A convertible preferred stock to an existing investor through the March 2018 Direct Registered Offering at a price of $8.31 per share. At the date of the financing, because the effective conversion rate of the preferred stock was less than the market value of the Company’s common stock, a beneficial conversion feature of $2.7 million was recorded as a discount to the convertible preferred stock and an increase to additional paid in capital. Because the preferred stock was perpetual and convertible at the option of the holder at any time, the Company fully amortized the discount related to the beneficial conversion feature as a deemed dividend which was recognized as an increase to accumulated deficit and net loss attributable to common stockholders. Effective on April 19, 2018, all outstanding shares of Series A convertible preferred stock were converted into shares of common stock at a conversion ratio of 1:1. Further, in May 2018, the Company filed a Certificate of Elimination of the Series A Convertible Preferred Stock de-authorizing the 3,000,581 shares of Series A convertible preferred stock. The Company had no outstanding preferred stock as of December 31, 2020 and 2019.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2020
Warrant [Abstract]
Warrants	1 2 . Warrants Equity Classified Common Stock Warrants In connection with a debt financing in December 2013, the Company issued warrants to purchase 128,231 shares of its common stock with an exercise price of $5.84 per share. These warrants are exercisable any time at the option of the holder until December 16, 2023. In connection with the merger of ViewRay, Inc. and ViewRay Technologies, Inc. in July 2015, or the Merger, in July and August 2015, the Company conducted a private placement offering as part of which the Company issued warrants, or the 2015 Placement Warrants, that provide the warrant holder the right to purchase 198,760 shares of common stock at an exercise price of $5.00 per share. The 2015 Placement Warrants are exercisable at any time at the option of the holder until the five-year During the year ended December 31, 2018, the Company issued 92,487 shares of its common stock upon the net exercise of 2015 Placement Warrants to purchase 159,010 shares. The remaining 39,750 shares of 2015 Placement Warrants expired in July and August 2020 and no ne remained outstanding at December 31, 2020 . In connection with the March 2018 Direct Registered Offering, the Company issued warrants to purchase 1,418,116 shares of common stock at an exercise price of $8.31 per share. The 2018 Offering Warrants became exercisable upon issuance and expire in March 2025 As separate classes of securities were issued in a bundled transaction, the gross proceeds from the March 2018 Direct Registered Offering of $59.1 million were allocated to common stock, Series A convertible preferred stock and the 2018 Offering Warrants based on their respective relative fair value upon issuance. The aggregate fair value of the 2018 Offering Warrants of $7.4 million was estimated using the Black-Scholes option-pricing model with the following assumptions: Upon Issuance Common Stock Warrants: Expected term (in years) 7.0 Expected volatility (%) 62.5% Risk-free interest rate (%) 2.8% Expected dividend yield (%) 0% The allocated proceeds from the 2018 Offering Warrants of $6.6 million was recorded in additional paid-in-capital. Liability Classified Common Stock Warrants In connection with the 2017 and 2016 Private Placements, the Company issued the 2017 and 2016 Placement Warrants, that provide the warrant holder the right to purchase 1,720,512 and 1,380,745 shares of common stock. The 2017 and 2016 Placement Warrants contain protection whereby the warrant holders will have the right to receive cash in the amount equal to the Black-Scholes value of the warrants upon the occurrence of a change in control, as defined in the agreement. The 2017 and 2016 Placement Warrants were accounted for as a liability at the date of issuance and are adjusted to fair value at each balance sheet date, with the change in fair value recorded as a component of other income (expense), net in the consolidated statements of operations and comprehensive loss. The key terms and activity of the 2017 and 2016 Placement Warrants are summarized as follows: Issuance Date Term Exercise Price Per Share Warrants Exercised during the Year Ended December 31, 2019 Warrants Outstanding at December 31, 2019 Warrants Exercised during the Year Ended December 31, 2020 Warrants Outstanding at December 31, 2020 2017 Placement Warrants January 2017 7 years $ 3.17 90,642 1,618,890 — 1,618,890 2016 Placement Warrants August and September 2016 7 years $ 2.95 593,352 537,263 — 537,263 Total 683,994 2,156,153 — 2,156,153 As separate classes of securities were issued in a bundled transaction, the gross proceeds of $26.1 million and $13.8 million from the 2017 and 2016 Private Placement were allocated first to the 2017 and 2016 Placement Warrants based on their fair value upon issuance, and the residuals were allocated to common stock. The fair value upon issuance of $3.4 million and $2.7 million were estimated using the Black-Scholes option-pricing model using the following assumptions: Upon Issuance 2017 Placement Warrants 2016 Placement Warrants Expected term (in years) 7.0 7.0 Expected volatility (%) 62.9% 61.6% Risk-free interest rate (%) 2.2% 1.4% Expected dividend yield (%) 0% 0% During the year ended December 31, 2020, the Company recorded a gain of $0.4 million and $0.1 million, respectively, related to the change in fair value of the 2017 and 2016 Placement Warrants. During the year ended December 31, 2019, the Company recorded a gain of $2.6 million and loss of $0.1 million, respectively, related to the change in fair value of the 2017 and 2016 Placement Warrants. During the year ended December 31, 201 8 , the Company recorded a gain of $ 5.4 million and $ 4.0 million, respectively, related to the change in fair value of the 2017 and 2016 Placement Warrants. The fair value of the 2017 and 2016 Placement Warrants at December 31, 2020 and 2019 was estimated using the Black-Scholes option-pricing model and the following weighted-average assumptions: 2017 Placement Warrants 2016 Placement Warrants December 31, 2020 December 31, 2019 December 31, 2020 December 31, 2019 Expected term (in years) 3.0 4.0 2.6 3.6 Expected volatility 86.9% 68.0% 86.3% 67.5% Risk-free interest rate 0.2% 1.7% 0.2% 1.6% Expected dividend yield 0% 0% 0% 0%

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	1 3 . Stock-Based Compensation As of December 31, 2020, the Company had an active stock-based incentive compensation plan, an employee stock purchase plan and an equity inducement plan: the 2015 Equity Incentive Award Plan (as amended and restated, the “2015 Plan”), the 2015 Employee Stock Purchase Plan (as amended and restated, the “ESPP”), and the 2018 Equity Inducement Award Program (the “2018 Plan”), respectively. All new equity compensation grants are issued under these three plans; however, outstanding awards previously issued under inactive plans will continue to vest and remain exercisable in accordance with the terms of the respective plans. The 2015 Plan and the 2018 Plan provide for the grant of stock and stock-based awards including stock options, restricted stock, stock units (including deferred stock units) and stock appreciation rights. Additionally, stock units may be issued as performance-based stock units to align stock compensation awards to the attainment of annual or long-term performance goals. As of December 31, 2020, there were 7.9 million shares available for grant under the 2015 Plan and 2018 Plan. Stock-Based Compensation Expense Total stock-based compensation expense recognized in the Company’s consolidated statements of operations and comprehensive loss is classified as follows (in thousands): Year Ended December 31, 2020 2019 2018 Cost of revenue $ 965 $ 2,645 $ 1,609 Research and development 2,288 3,910 2,681 Selling and marketing 1,091 1,365 736 General and administrative 18,461 11,525 9,143 Total stock-based compensation expense $ 22,805 $ 19,445 $ 14,169 Our stock-based compensation expense is based on the value of the portion of share-based payment awards that are ultimately expected to vest, assuming estimated forfeitures at the time of grant. Stock-based compensation relating to stock-based awards granted to consultants was insignificant for the years ended December 31, 2020, 2019 and 2018. Restricted Stock Units and Deferred Stock Units: The Company grants Restricted Stock Units, or RSUs, to its board of directors and employees for their services. Additionally, the Company grants Deferred Stock Units, or DSUs, to its board of directors at their election in lieu of retainer and committee service fees. The DSUs granted to board members are either fully vested upon issuance or vest over a period of time from the grant date and will be released and settled upon termination of the board member’s services, the occurrence of a change in control event, or the tenth anniversary of the grant date. The RSUs granted to employees and/or board members vest in equal annual or monthly installments over either two or three years from the grant date and are subject to the participants continuing service to the Company over that period. The weighted-average grant date fair value of RSUs granted in fiscal year 2020, 2019 and 2018 was $2.80 per share, $3.63 per share and $9.65 per share, respectively. A summary of the Company’s RSU activity and related information is as follows: Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2019 4,379,777 $ 5.14 RSUs granted 6,079,659 $ 2.80 RSUs vested (1,779,152 ) $ 5.69 RSUs cancelled or forfeited (633,885 ) $ 3.11 Unvested at December 31, 2020 8,046,399 $ 3.41 Vested and unreleased 177,007 Outstanding at December 31, 2020 8,223,406 The total grant date fair value of RSUs awarded was $17.0 million, $12.2 million and $17.0 million for the years ended December 31, 2020, 2019 and 2018, respectively. The total grant date fair value of RSUs vested was $10.1 million, $6.0 million and $0.3 million for the years ended December 31, 2020, 2019 and 2018, respectively. At December 31, 2020, total unrecognized stock-based compensation cost related to RSUs, net of estimated forfeitures, was $17.4 million, which is expected to be recognized over a weighted-average period of 1.9 years. As of December 31, 2020, 7.7 million shares of RSUs are expected to vest. Stock Options: Stock options awards are generally granted with an exercise price equal to the market price of our stock at the date of grant and with a four-years A summary of the Company’s stock option activity and related information is as follows: Number of Stock Options Outstanding Weighted- Average Exercise Price Weighted- Average Remaining Contractual (Years) Aggregate Intrinsic Value (In Options outstanding at December 31, 2019 11,165,846 $ 7.44 7.6 $ 1,907 Options granted 736,579 1.97 Options exercised (20,579 ) 0.72 Options cancelled or forfeited (3,739,498 ) 6.95 Options outstanding at December 31, 2020 8,142,348 $ 7.14 7.3 $ 2,638 Options exercisable at December 31, 2020 5,319,817 $ 7.20 6.8 $ 1,354 Options vested and expected to vest at December 31, 2020 7,875,294 $ 7.18 7.2 $ 2,438 The weighted-average grant date fair value of options granted to employees was $1.20, $4.67 and $4.89 per share for the years ended December 31, 2020, 2019 and 2018. The grant date fair value of options vested was $9.2 million, $14.4 million and $6.3 million, respectively, for the years ended December 31, 2020, 2019 and 2018, respectively. Aggregate intrinsic value represents the difference between the estimated fair value of the underlying common stock and the exercise price of outstanding, in-the-money options. The aggregate intrinsic value of options exercised was nil, $7.8 million and $17.7 million for the years ended December 31, 2020, 2019 and 2018, respectively. At December 31, 2020, total unrecognized stock-based compensation cost related to stock options granted to employees, net of estimated forfeitures, was $10.1 million, which is expected to be recognized over a weighted-average period of 2.0 years. The determination of the fair value of stock options on the date of grant using an option-pricing model is affected by the estimated fair value of the Company’s common stock, as well as assumptions regarding a number of complex and subjective variables. The variables used to calculate the fair value of stock options using the Black-Scholes option-pricing model include actual and projected employee stock option exercise behaviors, expected price volatility of the Company’s common stock, the risk-free interest rate and expected dividends. Each of these inputs is subjective and generally requires significant judgment to determine. The risk-free interest rate is based on the zero-coupon U.S. Treasury notes, with maturities similar to the expected term of the options. The Company has not paid and does not anticipate paying cash dividends on its common stock; therefore, the expected dividend yield is assumed to be zero. During the fourth quarter of 2020, the Company began to determine volatility by solely using the Company’s own historical volatility measurements, since more than four years of historical data became available in the public market. Prior to the fourth quarter of 2020, the Company determined the volatility for stock options granted based on the average historical price volatility for the Company and industry peers over a period equivalent to the expected term of the stock options grants. The forfeiture rate of stock options is estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Forfeitures have been estimated by the Company based upon historical and expected forfeiture experience. The fair value of employee stock options was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended December 31, 2020 2019 2018 Expected term (in years) 6.0 6.0 6.0 Expected volatility (%) 68.8% 60.7% 60.4% Risk-free interest rate (%) 0.7% 2.4% 2.8% Expected dividend yield (%) 0% 0% 0% Employee Stock Purchase Plan In July 2015, the Company adopted the Employee Stock Purchase Plan, or ESPP. Certain employees, as defined by the ESPP, are eligible to participate in the ESPP if employed by the Company for at least 20 hours per week during at least five months per calendar year. Participating employees may contribute up to the lesser of 15% of their eligible earnings or $30,000 during each offering period, provided that in no event shall a participating employee be permitted to purchase more than 3,000 shares of common stock during each offering period. During 2020, the first offering period provided to eligible employees was April 1, 2020 through June 30, 2020. Beginning July 1, 2020, the offering plan is six months and are expected to remain consistent going forward. The purchase price of common stock purchased under the ESPP is currently equal to 85% of the lesser of the fair market value of a share of common stock on: 1) the first trading day of an offering period and 2) the last trading of each offering period. At December 31, 2020 and 2019, 3.5 million shares and 2.7 million shares were reserved for issuance under the ESPP, respectively. No more than 3.5 million shares of common stock may be issued under the ESPP. As of December 31, 2020, 0.2 million shares have been issued under the ESPP and 3.3 million shares remained available for future issuance under the ESPP. Purchase rights granted under the ESPP are valued using the Black-Scholes pricing model. During 2020, the grant date for the two offering periods was April 1, 2020 and July 1, 2020. As such, the expected stock price volatility for the Company’s common stock for the ESPP purchase rights was estimated by taking the average historic price volatility of the Company industry peers based on daily price observations over a period equivalent to the expected term of the offering period. The expected term represents the period of time the ESPP purchase rights are expected to be outstanding and approximates the offering period. The latest offering period and related purchase was completed on December 31, 2020. As such, there was no unrecognized compensation cost related to the ESPP as of December 31, 2020. Total compensation expense was $0.1 million for the year ended December 31, 2020. There was no compensation expense related to the ESPP for the years ended December 31, 2019 or 2018. The fair value of each purchase right granted under the ESPP was estimated on the date of grant using the Black-Scholes option-pricing model with the following assumptions: Year Ended December 31, 2020 2019 2018 Expected term (in years) 0.25 - 0.50 N/A N/A Expected volatility (%) 83.0% N/A N/A Risk-free interest rate (%) 0.09% - 0.17% N/A N/A Expected dividend yield (%) 0% N/A N/A

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	1 4 . Income Taxes On March 27, 2020, the Coronavirus Aid, Relief and Economic Security (CARES) Act was signed into law. The CARES Act includes provisions relating to refundable payroll tax credits, net operating loss carryback periods, alternative minimum tax credit refunds, modifications to the net interest deduction limitations and technical corrections to the tax deprecation methods for qualified improvement property. The impact of the CARES act is estimated to be immaterial on the Company’s income tax expense. Income Tax Expense The following reconciles the differences between income taxes computed at the federal income tax rate and the provision for income taxes: Year Ended December 31, 2020 2019 2018 Expected income tax benefit at the federal statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 0.0 0.0 0.0 Change in federal statutory rate 0.0 0.0 0.0 Non-deductible items and other (3.4 ) (2.8 ) (0.2 ) Federal and state credits 0.5 0.6 0.7 Change in valuation allowance (18.1 ) (18.8 ) (21.5 ) Total 0.0 % 0.0 % 0.0 % Deferred income taxes reflect the net effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The principal components of the Company’s net deferred tax assets consisted of the following at December 31, 2020 and 2019 (in thousands): Year Ended December 31, 2020 2019 Deferred tax assets Net operating loss carryforwards $ 121,346 $ 101,967 Research and development tax credits 6,949 5,872 Reserves and accruals 4,984 5,720 Operating lease liability 2,588 3,088 Other 4,702 3,422 Total deferred tax assets 140,569 120,069 Less: Valuation allowance (138,214 ) (117,229 ) Net deferred tax assets 2,355 2,840 Deferred tax liabilities Right-of-use assets (2,355 ) (2,840 ) Total deferred tax liabilities (2,355 ) (2,840 ) Net deferred tax assets $ — $ — The Company maintains a valuation allowance related to its deferred tax asset position when management believes it is more likely than not that the net deferred tax assets will not be realized in the future. The Company’s valuation allowance increased by $21.0 million and $25.2 million during the year ended December 31, 2020 and 2019, respectively. At December 31, 2020, the Company had federal net operating loss carryforwards of $527.1 million, which begin to expire in the year ending December 31, 2024, and $303.4 million related to state net operating loss carryforwards, which begin to expire in the year ending December 31, 2020. The Company had federal research and development tax credit carryforwards of $6.3 million, and state carryforwards of $3.9 million at the year ended December 31, 2020. These credits begin to expire in the year ending December 31, 2027. Under the provisions of the Internal Revenue Code, or IRC, net operating loss and credit carryforwards and other tax attributes may be subject to limitation if there has been a significant change in ownership of the Company, as defined by the IRC. The Company performed a Section 382 analysis in February of 2020 and three ownership changes were identified, which had a corresponding limitation of tax attributes. Future owner or equity shifts could result in additional limitations on net operating loss and credit carryforwards. Because of the net operating loss and credit carryforwards, all of the Company’s federal tax returns and state returns since the year ended December 31, 2004 remain subject to federal and California examination. The Company accounts for uncertain tax positions using a “more-likely-than-not” threshold. The evaluation of uncertain tax positions is based on factors including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. The Company evaluates these tax positions on an annual basis. In addition, the Company also accrues for potential interest and penalties related to unrecognized tax benefits in income tax expense. At December 31, 2020 and 2019, the Company’s unrecognized tax benefits consist of the following (in thousands): Year Ended December 31, 2020 2019 Unrecognized tax benefit, beginning of period $ 2,158 $ 1,595 Gross increases — current year tax positions 548 595 Gross increases — prior year tax positions — — Gross decreases — prior year tax positions (25 ) (32 ) Unrecognized tax benefit, end of period $ 2,681 $ 2,158

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2020
Postemployment Benefits [Abstract]
Employee Benefits	1 5 . Employee Benefits The Company has a 401(k) Plan which covers its eligible employees. The 401(k) Plan permits the participants to defer a portion of their compensation in accordance with the provisions of Section 401(k) of the IRC. Participant contributions are limited to a maximum annual amount as set periodically by the IRC. The Company started to match 50% of eligible participant contributions up to 6% annual contribution during the year ended December 31, 2018. The Company’s matching contribution to the 401(k) Plan was $1.1 million, $0.9 million, and $0.5 million for the years ended December 31, 2020, 2019, and 2018, respectively.

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Loss per Share	1 6 . Net Loss per Share The following table sets forth the computation of the Company’s basic and diluted net loss per share for the periods presented (in thousands, except share and per share data): Year Ended December 31, 2020 2019 2018 Net loss attributable to common stockholders, basic and diluted $ (107,908 ) $ (120,199 ) $ (79,124 ) Weighted-average common shares used in computing net loss per share, basic and diluted 147,895,561 102,001,954 81,123,140 Net loss per share, basic and diluted $ (0.73 ) $ (1.18 ) $ (0.98 ) Diluted earnings per share (“EPS”) includes the dilutive effect of common stock equivalents and is computed using the weighted-average number of common stock and common stock equivalents outstanding during the reporting period. Diluted EPS for the years ended December 31, 2020, 2019, and 2018 excluded common stock equivalents because the effect of their inclusion would be anti-dilutive or would decrease the reported loss per share. The following table sets forth securities outstanding that could potentially dilute the calculation of diluted earnings per share: Year Ended December 31, 2020 2019 2018 Options to purchase common stock 8,142,348 11,165,846 11,603,708 Warrants to purchase common stock - liability classified 2,156,153 2,156,153 2,840,147 Warrants to purchase common stock - equity classified 1,418,116 1,457,866 1,586,097 Unvested restricted stock units 8,046,399 4,379,777 1,736,234 As previously mentioned, on January 4, 2021, the Company entered into an underwriting agreement with the 2021 Underwriters, with respect to the issuance and sale of 11,856,500 shares of our common stock, which included the full exercise of the 2021 Underwriters’ option to purchase additional shares, at a price to the public of $4.85 per share.

Segment and Geographic Informat

Segment and Geographic Information	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment and Geographic Information	1 7 . Segment and Geographic Information The Company has one business activity, which is radiation therapy technology combined with magnetic resonance imaging, and operates in one reportable segment. The Company’s chief operating decision-maker, its chief executive officer, reviews its operating results on an aggregate basis for purposes of allocating resources and evaluating financial performance. Also, the Company does not have segment managers as the Company manages its operations as a single operating segment. The following table sets forth revenue by geographic area based on the shipping address of the customers’ location (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 16,167 $ 46,236 $ 34,231 Taiwan 10,710 — 4,680 France 7,025 12,235 5,812 United Kingdom 6,060 5,974 — Germany 839 7,393 13,727 Rest of world 16,216 15,944 22,512 Total revenue $ 57,017 $ 87,782 $ 80,962 At December 31, 2020 and 2019, nearly all long-lived assets are located in the United States.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	1 8 . Related Party Transactions As discussed in Note 8, the Company pays a royalty to UFRF, a stockholder in the Company, related to a licensing agreement. In November 2019, the Company entered into a distribution agreement with Chindex Shanghai International Trading Company Limited, or Chindex, which became effective in February 2020. Chindex is a subsidiary of Fosun International Limited, or Fosun. Kevin Xie, Ph.D., a member of the Company’s board of directors, was previously designated by Fosun for election to the board pursuant to a Securities Purchase Agreement related to the Company’s 2017 direct registered offering of common stock. Under the distribution agreement, Chindex will act as the Company’s distributor and regulatory agent for the sale and delivery of its MRIdian products within the People’s Republic of China, excluding Hong Kong, Macau and Taiwan. The distribution agreement has an initial term of five years with an option to renew for an additional five years. Under the distribution agreement, the Company will supply its products and services to Chindex based on an agreed upon price between the Company and Chindex. In accordance with the agreement, Chindex agreed to pay ViewRay an upfront fee, portions of which may be refundable under certain conditions, of $3.5 million, payable in three installments: (i) the first installment of $1.5 million due approximately 60 days after the effectiveness of the distribution agreement; (ii) the second installment of $1.0 million due on the first anniversary from the effective date of the agreement; and (iii) the third installment of $1.0 million due on the second anniversary from the effective date of the agreement. The Company received payment of the first installment during the fourth quarter of 2020.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	19. Subsequent Events The Company has evaluated the period subsequent to December 31, 2020, for material events that did not exist at the balance sheet date but arose after that date and determined that no additional subsequent events arose that should be disclosed in order to keep the financial statements from being misleading, except as otherwise disclosed herein including with respect to the January 2021 Public Offering of Common Stock. On March 3, 2021, we entered into a sub-lease agreement to lease approximately 12,800 square feet of office space in Denver, Colorado. The sub-lease will commence on September 1, 2021 and will expire October 31, 2024.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared in conformity with U.S. GAAP, and pursuant to the rules and regulations of the Securities and Exchanges Commission, or SEC. The consolidated financial statements include the accounts of ViewRay, Inc. and its wholly-owned subsidiary, ViewRay Technologies, Inc. All inter-company accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported and disclosed in the consolidated financial statements and accompanying notes. Such estimates include, but are not limited to, allocation of revenue to multiple performance obligations within an arrangement, inventory write-downs to reflect net realizable value, assumptions used in the valuation of stock-based awards and warrant liability, and valuation allowances against deferred tax assets. Actual results could differ from these estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. The Company deposits its cash primarily in checking and money market accounts. The carrying amounts of the Company’s cash equivalents approximate their fair values due to their short maturities.
Restricted Cash	Restricted Cash At December 31, 2020 and 2019, the Company had an aggregate of $1.4 million and $0.9 million, respectively, of outstanding letters of credit related to its operating leases and its contractual obligations with distributors and customers. The letters of credit are collateralized by a restricted cash deposit account, which is presented as part of noncurrent assets on the balance sheets because the Company is not certain when the restriction will be lifted on the collateralized letters of credit. At December 31, 2020 and 2019, no amounts were drawn on the letters of credit. The restricted cash balance as of December 31, 2019 also includes collateral of $0.5 million for credit card accounts.
Concentration of Credit Risk, Other Risks and Uncertainties	Concentration of Credit Risk, Other Risks and Uncertainties Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. Cash and cash equivalents are deposited in checking and money market accounts with various financial institutions. At times, cash balances may be in excess of the amounts insured by the Federal Deposit Insurance Corporation. Management believes the financial risk associated with these balances is minimal and has not experienced any losses to date. The Company performs periodic credit evaluations of its customers’ financial condition and generally requires deposits from its customers. The Company’s accounts receivable were derived from billings to customers. The Company’s customers representing greater than 10% of accounts receivable or revenue for the periods presented were as follows: Revenue Accounts Receivables Year Ended December 31, December 31, Customers 2020 2019 2018 2020 2019 Customer A 11% 30% Customer B 25% Customer C 10% 20% Customer D 34% Customer E 25% Customer F 15% Customer G 19% Customer H 12% 14% The Company’s future results of operations involve a number of risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, rapid technological change, continued acceptance of MRIdian, competition from substitute products and larger companies, protection of proprietary technology, ability to maintain distributor relationships and dependence on key individuals. Furthermore, new products to be developed by the Company require approval from the FDA or other international regulatory agencies prior to commercial sales. There can be no assurance that the Company’s future products will receive the necessary clearances. The Company relies on a concentrated number of suppliers to manufacture essentially all of the components used in MRIdian. The Company’s suppliers may encounter problems during manufacturing due to a variety of reasons, including failure to comply with applicable regulations, including the FDA’s Quality System Regulation, equipment malfunction and environmental factors, any of which could delay or impede our ability to meet demand.
Accounts Receivables and Allowance for Doubtful Accounts	Accounts Receivables and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount, net of any allowance for doubtful accounts, and do not bear interest. The allowance for doubtful accounts, if any, is based on the assessment of the collectability of customer accounts. There was no allowance for doubtful accounts recorded at December 31, 2020 and 2019.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Financial instruments consist of cash and cash equivalents, accounts receivable, restricted cash, prepaid expenses and other current assets, accounts payable, accrued liabilities, warrant liability and long-term debt. Cash equivalents are stated at amortized cost, which approximates fair value at the balance sheet dates, due to the short period of time to maturity. Accounts receivable, prepaid expenses and other current assets, accounts payable, accrued liabilities current portion of long-term debt are stated at their carrying value, which approximates fair value due to the short time to the expected receipt or payment date. The warrant liability is carried at fair value. The carrying amount of the Company’s long-term debt approximates its fair value as the stated interest rate approximates market rates currently available to the Company. Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, as follows: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices 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 assets or liabilities. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The assets’ or liabilities’ fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.
Inventory and Deposits on Purchased Inventory	Inventory and Deposits on Purchased Inventory Inventory consists of purchased components for assembling MRIdian systems and other direct and indirect costs associated with MRIdian system installation. Inventory is stated at the lower of cost or net realizable value. All inventories expected to be placed in service during the normal operating cycle of the Company for the delivery and assembly of MRIdian systems, including items expected to be on hand for more than one year, are classified as current assets. Excess and obsolete inventories are written down based on historical sales and forecasted demand, as judged by management. The Company reduces the carrying value of its inventory for the difference between cost and net realizable value and records a charge to cost of product revenues. The Company recorded an inventory lower of cost and net realizable value adjustment of $ 0.2 million and $ 0.3 million during the years ended December 31, 2020 and 2018 , respectively. There was no lower of cost and net realizable value adjustment during the year ended December 31, 2019 . The Company records inventory items which have been paid for but not yet received and for which title has not yet transferred to the Company as deposits on purchased inventory. Deposits on purchased inventory are included within current assets as the related inventory items are expected to be received and used in MRIdian systems within the Company’s normal operating cycle. The Company assesses the recoverability of deposits on purchased inventory based on credit assessments of the vendors and their history supplying these assets. At December 31, 2020, the Company did not have any instances whereby deposits for purchased inventory were written off or the purchased inventory was not delivered.
Shipping and Handling Costs	Shipping and Handling Costs Shipping and handling costs for product shipments to customers are included in cost of product revenue. Shipping and handling costs incurred for inventory purchases are capitalized in inventory and expensed in cost of product revenue.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost. Depreciation is computed over the estimated useful lives, ranging from two to 15 years, of the related assets using the straight-line method. Acquired software is recorded at cost. Amortization of acquired software generally occurs over three years using the straight-line method. Leasehold improvements are amortized on a straight-line basis over the shorter of the useful life or term of the lease. Demonstration units, which are the Company products used for demonstration purpose for customers and/or potential customers, and generally not intended to be sold, are amortized using the straight-line method. Depreciation and amortization periods for property and equipment are as follows: Property and Equipment Estimated Useful Life Prototype 2 - 10 years Machinery and equipment 3 - 15 years Furniture and fixture 5 - 10 years Software 3 years Leasehold improvements Lesser of estimated useful life or remaining lease term
Leases	Leases We determine if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use (“ROU”) assets, and operating lease liabilities, current and noncurrent, on our consolidated balance sheets. We currently do not have any finance lease arrangements. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date of the lease in determining the present value of future payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Our lease terms may include an option to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Leases with an initial term of 12 months or less are not recorded on the balance sheet; we recognize lease expense for these leases on a straight-line basis over the lease term.
Asset Retirement Obligations	Asset Retirement Obligations In connection with two lease agreements and subsequent amendments, the Company has a legal obligation to remove long-lived assets constructed on the leased properties and to restore the leased properties to their original condition. The Company records the fair value of the asset retirement obligation in the period in which it is incurred. The fair value is measured based upon the present value of the expected future payments at inception and remeasured upon the extension of the respective lease agreement. The liability is accreted to its present value each period and the capitalized cost is depreciated over the remaining lease term. Accretion expense is calculated by applying the effective interest rate to the carrying amount of the liability at the beginning of each period. The effective interest rate is the credit-adjusted risk-free rate applied when the liability was initially measured at inception and remeasured upon the lease extension, when applicable. At December 31, 2020, the Company had outstanding asset retirement obligations of $0.9 million, which was included in other long-term liabilities in the accompanying consolidated balance sheets. For the years ended December 31, 2020, 2019 and 2018, the Company recognized accretion expenses of $63 thousand, $43 thousand and $33 thousand in the accompanying statements of operations and comprehensive loss.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews the recoverability of long-lived assets, including equipment, leasehold improvements, software and intangible assets when events or changes in circumstances occur that indicate that the carrying value of the asset may not be recoverable. The assessment of possible impairment is based on the ability to recover the carrying value of the assets from the expected future cash flows (undiscounted and without interest charge) of the related operations. If these cash flows are less than the carrying value of such assets, an impairment loss for the difference between the estimated fair value and carrying value is recorded. There was no impairment loss recognized during the years ended December 31, 2020 , 2019 and 2018 .
Revenue Recognition	Revenue Recognition The Company derives revenues primarily from the sale of MRIdian systems and related services as well as support and maintenance services on sold systems. The Company accounts for revenue contracts with customers by applying the requirements of ASC 606, Revenues from Contracts with Customers, • identification of the contract, or contracts, with a customer; • identification of the performance obligations in the contract • determination of the transaction price; • allocation of the transaction price to the performance obligations in the contract; and • recognition of revenue when, or as, the Company satisfies a performance obligation. In all sales arrangements, revenues are recognized when control of the promised goods or services are transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to receive in exchange for those goods or services. For sales of MRIdian systems, beginning in the second quarter of 2019, the Company determined that the MRIdian system and installation of the MRIdian system, which had previously been one performance obligation, are now two performance obligations as they are capable of being distinct and are distinct within the context of the system contracts. This change occurred due primarily to changes in facts and circumstances, whereby there are now readily available resources outside the Company that can perform the system installations. For sales of the related support and maintenance services, a time-elapsed method is used to measure progress toward complete satisfaction of performance obligations and service revenue is recognized ratably over the service contract term, which is typically 12 months. Additional details regarding revenue recognition are included in Note 7 – Revenue .
Research and Development Costs	Research and Development Costs Expenditures, including payroll, contractor expenses and supplies, for research and development of products and manufacturing processes are expensed as incurred. Costs for the development of new software products and substantial enhancements to existing software products are expensed as incurred until technological feasibility has been established, at which time any additional costs would be capitalized. No costs associated with the development of software have been capitalized as the Company believes its current software development process is completed concurrent with the establishment of technological feasibility.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation expense for all share-based payment awards granted is based on the grant date fair value. The Company uses the Black-Scholes option-pricing model to estimate the fair value of stock options. The Black-Scholes option-pricing model requires the use of highly subjective assumptions, including the options’ expected term and the price volatility of the underlying stock
Deferred Commissions	Deferred Commissions Deferred commissions are the direct and incremental costs directly associated with the MRIdian system contracts with customers, which primarily consist of sales commissions to our direct sales force. The commissions are deferred and expensed in proportion to the revenue recognized upon the acceptance of the MRIdian system. At December 31, 2020 and 2019, the Company had $2.4 million and $2.1 million, respectively, in deferred commissions recorded as part of prepaid expenses and other current assets on the consolidated balance sheets.
Income Taxes	Income Taxes The Company uses the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Deferred tax expense or benefit is the result of changes in the deferred tax assets and liabilities. Valuation allowances are established when necessary to reduce deferred tax assets where, based upon the available evidence, management concludes that it is more-likely-than not that the deferred tax assets will not be realized. Because of the uncertainty of the realization of the deferred tax assets, the Company has recorded a full valuation allowance against its net deferred tax assets. In evaluating the ability to recover its deferred income tax assets, the Company considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction-by-jurisdiction basis. In the event the Company was to determine that it would be able to realize its deferred income tax assets in the future in excess of their net recorded amount, it would make an adjustment to the valuation allowance which would reduce the provision for income taxes. Reserves are provided for tax benefits for which realization is uncertain. Such benefits are only recognized when the underlying tax position is considered more likely than not to be sustained on examination by a taxing authority, assuming they possess full knowledge of the position and facts. It is the Company’s policy to include any penalties and interest related to income taxes in its income tax provision; however, the Company currently has no penalties or interest related to income taxes. The earliest year that the Company is subject to examination is the year ended December 31, 2004.
Warrant Liability	Warrant Liability Certain warrants to purchase common stock provide for cash settlement in the event of a change in control, and are recorded as liabilities on the balance sheets at fair value upon issuance (see Note 12). These warrants are subject to re-measurement to fair value at each balance sheet date. Any changes in fair value are recognized in the consolidated statements of operations and comprehensive loss as other income (expense), net. Upon exercise of the warrants, the related warrant liability will be reclassified to additional paid-in capital.
Net Loss per Share	Net Loss per Share The Company’s basic net loss attributable to common stockholders per share is calculated by dividing net loss by the weighted-average number of shares of common stock outstanding for the period. Contingently issuable shares are included in the computation of basic net loss per share as of the date that all necessary conditions have been satisfied and issuance of the shares is no longer contingent. The diluted net loss per share is computed by giving effect to all potential common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, stock options, restricted stock units and warrants to purchase common stock are considered to be common stock equivalents but have been excluded from the calculation of diluted net loss per share as their effect is anti-dilutive.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, Financial Instruments – Credit Losses In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, In March 2020, the FASB issued ASU 2020-04, Facilitation of the Effects of Reference Rate Reform on Financial Reporting In August 2020, the FASB issued ASU 2020-06, an update to Accounting Standard Codification (“ASC”) Topic 470, Subtopic – 20, Debt – Debt with Conversion and Other Options, and ASC Topic 815, Subtopic – 40, Derivatives and Hedging – Contracts in Entity's Own Equity. The ASU simplifies the guidance for certain financial instruments with characteristics of liability and equity, including convertible instruments and contracts on an entity’s own equity by reducing the number of accounting models for convertible instruments and amends guidance in ASC Topic 260, Earnings Per Share, relating to the computation of earnings per share for convertible instruments and contracts on an entity’s own equity. The ASU is effective for interim and annual reporting periods in fiscal years that begin after December 15, 2021, with early adoption permitted for fiscal years that begin after December 15, 2020. The Company is currently evaluating the impact this guidance may have on its consolidated financial statements and related disclosures.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Effective January 1, 2020

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of Customers Representing Greater than 10% of Accounts Receivable and Revenue	The Company’s customers representing greater than 10% of accounts receivable or revenue for the periods presented were as follows: Revenue Accounts Receivables Year Ended December 31, December 31, Customers 2020 2019 2018 2020 2019 Customer A 11% 30% Customer B 25% Customer C 10% 20% Customer D 34% Customer E 25% Customer F 15% Customer G 19% Customer H 12% 14%
Schedule of Depreciation and Amortization Periods for Property and Equipment	Depreciation and amortization periods for property and equipment are as follows: Property and Equipment Estimated Useful Life Prototype 2 - 10 years Machinery and equipment 3 - 15 years Furniture and fixture 5 - 10 years Software 3 years Leasehold improvements Lesser of estimated useful life or remaining lease term

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Schedule of Property and Equipment, Net	Property and equipment consisted of the following (in thousands): December 31, 2020 2019 Prototype $ 17,711 $ 16,419 Machine and equipment 17,486 15,816 Leasehold improvements 14,196 6,718 Furniture and fixtures 1,295 1,284 Software 1,389 1,389 Construction in progress 486 4,176 Property and equipment, gross 52,563 45,802 Less: accumulated depreciation and amortization (28,501 ) (22,403 ) Property and equipment, net $ 24,062 $ 23,399
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): December 31, 2020 2019 Accrued payroll and related benefits $ 12,810 $ 9,577 Accrued accounts payable 2,810 4,764 Payroll withholding tax, sales and other tax payable 1,398 1,066 Accrued legal and accounting 305 1,175 Product upgrade reserve 1,500 3,794 Other 458 1,014 Total accrued liabilities $ 19,281 $ 21,390
Schedule of Deferred Revenue	Deferred revenue consisted of the following (in thousands): December 31, 2020 2019 Deferred revenue: Product $ 1,888 $ 3,141 Services 8,857 8,473 Distribution rights 1,921 2,396 Total deferred revenue 12,666 14,010 Less: current portion of deferred revenue (10,094 ) (10,457 ) Noncurrent portion of deferred revenue $ 2,572 $ 3,553
Schedule of Other Long Term Liabilities	Other long-term liabilities consisted of the following (in thousands): December 31, 2020 2019 Accrued interest, noncurrent portion $ 99 $ 516 Asset retirement obligation 857 861 Total other-long term liabilities $ 956 $ 1,377

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Financial Liabilities	The following table sets forth the fair value of the Company’s financial liabilities by level within the fair value hierarchy (in thousands): At December 31, 2020 Level 1 Level 2 Level 3 Total 2017 Placement Warrants Liability $ — $ — $ 3,675 $ 3,675 2016 Placement Warrants Liability — — 1,189 1,189 Total Warrant Liability $ — $ — $ 4,864 $ 4,864 At December 31, 2019 Level 1 Level 2 Level 3 Total 2017 Placement Warrants Liability $ — $ — $ 4,043 $ 4,043 2016 Placement Warrants Liability — — 1,330 1,330 Total Warrant Liability $ — $ — $ 5,373 $ 5,373
Summary of Changes in Fair Value of Level 3 Financial Liabilities	The following table summarizes the changes in the fair value of the Company’s Level 3 financial liabilities (in thousands): Year Ended December 31, 2020 2019 2018 Fair value, beginning of period $ 5,373 $ 11,844 $ 22,420 Change in fair value of Level 3 financial liabilities (509 ) (2,496 ) (9,379 ) Fair value of 2016 Placement Warrants at exercise — (3,457 ) (1,187 ) Fair value of 2017 Placement Warrants at exercise — (518 ) (10 ) Fair value, end of period $ 4,864 $ 5,373 $ 11,844

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Scheduled Future Payments on Term Loan	The Company’s scheduled future payments on the SVB Term Loan at December 31, 2020 are as follows (in thousands): Year Ended December 31, 2021 $ — 2022 3,222 2023 19,333 2024 19,333 2025 16,112 Total future principal payments 58,000 Less: unamortized debt discount (1,060 ) Carrying value of long-term debt 56,940 Less: current portion — Long-term portion $ 56,940

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Schedule of Cash Flow Transactions Arising From Lease Transactions	During the years ended December 31, 2020 and 2019, the Company recognized the following cash flow transactions arising from lease transactions (in thousands): For the Year Ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities $ 3,145 $ 2,451 Right-of-use assets obtained in exchange for new operating lease liabilities 643 1,647
Schedule of Future Minimum Payments and Interest Expense for Operating Leases	At December 31, 2020, the future payments and interest expense for the operating leases are as follows (in thousands): Year Ended December 31, Future Payments 2021 $ 2,847 2022 2,659 2023 2,738 2024 2,774 2025 2,096 Thereafter 147 Total undiscounted cash flows $ 13,261 Less: imputed interest (2,129 ) Present value of lease liabilities $ 11,132

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Schedule of Revenue Disaggregated by Types and Geography	The following table presents revenue disaggregated by type and geography (in thousands): Years Ended December 31, U.S. 2020 2019 2018 Product $ 8,428 $ 41,985 $ 32,265 Service 7,739 4,251 1,966 Total U.S. revenue $ 16,167 $ 46,236 $ 34,231 Outside of U.S. ("OUS") Product $ 34,314 $ 37,519 $ 44,361 Service 6,061 3,552 1,895 Distribution rights 475 475 475 Total OUS revenue $ 40,850 $ 41,546 $ 46,731 Total Product $ 42,742 $ 79,504 $ 76,626 Service 13,800 7,803 3,861 Distribution rights 475 475 475 Total revenue $ 57,017 $ 87,782 $ 80,962

Warrants (Tables)

Warrants (Tables)	12 Months Ended
	Dec. 31, 2020
Warrant [Abstract]
Summary of Assumptions using Black- Scholes Option Pricing Model to estimate fair value	The aggregate fair value of the 2018 Offering Warrants of $7.4 million was estimated using the Black-Scholes option-pricing model with the following assumptions: Upon Issuance Common Stock Warrants: Expected term (in years) 7.0 Expected volatility (%) 62.5% Risk-free interest rate (%) 2.8% Expected dividend yield (%) 0% Upon Issuance 2017 Placement Warrants 2016 Placement Warrants Expected term (in years) 7.0 7.0 Expected volatility (%) 62.9% 61.6% Risk-free interest rate (%) 2.2% 1.4% Expected dividend yield (%) 0% 0% The fair value of the 2017 and 2016 Placement Warrants at December 31, 2020 and 2019 was estimated using the Black-Scholes option-pricing model and the following weighted-average assumptions: 2017 Placement Warrants 2016 Placement Warrants December 31, 2020 December 31, 2019 December 31, 2020 December 31, 2019 Expected term (in years) 3.0 4.0 2.6 3.6 Expected volatility 86.9% 68.0% 86.3% 67.5% Risk-free interest rate 0.2% 1.7% 0.2% 1.6% Expected dividend yield 0% 0% 0% 0%
Schedule of Key Terms of Placement Warrants	The key terms and activity of the 2017 and 2016 Placement Warrants are summarized as follows: Issuance Date Term Exercise Price Per Share Warrants Exercised during the Year Ended December 31, 2019 Warrants Outstanding at December 31, 2019 Warrants Exercised during the Year Ended December 31, 2020 Warrants Outstanding at December 31, 2020 2017 Placement Warrants January 2017 7 years $ 3.17 90,642 1,618,890 — 1,618,890 2016 Placement Warrants August and September 2016 7 years $ 2.95 593,352 537,263 — 537,263 Total 683,994 2,156,153 — 2,156,153

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Summary of Stock-Based Compensation Expense	Total stock-based compensation expense recognized in the Company’s consolidated statements of operations and comprehensive loss is classified as follows (in thousands): Year Ended December 31, 2020 2019 2018 Cost of revenue $ 965 $ 2,645 $ 1,609 Research and development 2,288 3,910 2,681 Selling and marketing 1,091 1,365 736 General and administrative 18,461 11,525 9,143 Total stock-based compensation expense $ 22,805 $ 19,445 $ 14,169
Summary of RSU Activity	A summary of the Company’s RSU activity and related information is as follows: Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2019 4,379,777 $ 5.14 RSUs granted 6,079,659 $ 2.80 RSUs vested (1,779,152 ) $ 5.69 RSUs cancelled or forfeited (633,885 ) $ 3.11 Unvested at December 31, 2020 8,046,399 $ 3.41 Vested and unreleased 177,007 Outstanding at December 31, 2020 8,223,406
Summary of Company's Stock Option Activity and Related Information	A summary of the Company’s stock option activity and related information is as follows: Number of Stock Options Outstanding Weighted- Average Exercise Price Weighted- Average Remaining Contractual (Years) Aggregate Intrinsic Value (In Options outstanding at December 31, 2019 11,165,846 $ 7.44 7.6 $ 1,907 Options granted 736,579 1.97 Options exercised (20,579 ) 0.72 Options cancelled or forfeited (3,739,498 ) 6.95 Options outstanding at December 31, 2020 8,142,348 $ 7.14 7.3 $ 2,638 Options exercisable at December 31, 2020 5,319,817 $ 7.20 6.8 $ 1,354 Options vested and expected to vest at December 31, 2020 7,875,294 $ 7.18 7.2 $ 2,438
Schedule of Weighted-Average Assumptions Used in Black-Scholes Option-Pricing Model to Estimate Fair Value of Employee Stock Options at Grant Date	The fair value of employee stock options was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended December 31, 2020 2019 2018 Expected term (in years) 6.0 6.0 6.0 Expected volatility (%) 68.8% 60.7% 60.4% Risk-free interest rate (%) 0.7% 2.4% 2.8% Expected dividend yield (%) 0% 0% 0%
2015 Employee Stock Purchase Plan
Schedule of Weighted-Average Assumptions Used in Black-Scholes Option-Pricing Model to Estimate Fair Value of Employee Stock Purchases at Grant Date	The fair value of each purchase right granted under the ESPP was estimated on the date of grant using the Black-Scholes option-pricing model with the following assumptions: Year Ended December 31, 2020 2019 2018 Expected term (in years) 0.25 - 0.50 N/A N/A Expected volatility (%) 83.0% N/A N/A Risk-free interest rate (%) 0.09% - 0.17% N/A N/A Expected dividend yield (%) 0% N/A N/A

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of Differences Between Federal Income Tax Rate and Effective Tax Rate	The following reconciles the differences between income taxes computed at the federal income tax rate and the provision for income taxes: Year Ended December 31, 2020 2019 2018 Expected income tax benefit at the federal statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 0.0 0.0 0.0 Change in federal statutory rate 0.0 0.0 0.0 Non-deductible items and other (3.4 ) (2.8 ) (0.2 ) Federal and state credits 0.5 0.6 0.7 Change in valuation allowance (18.1 ) (18.8 ) (21.5 ) Total 0.0 % 0.0 % 0.0 %
Schedule of Deferred Tax Assets	The principal components of the Company’s net deferred tax assets consisted of the following at December 31, 2020 and 2019 (in thousands): Year Ended December 31, 2020 2019 Deferred tax assets Net operating loss carryforwards $ 121,346 $ 101,967 Research and development tax credits 6,949 5,872 Reserves and accruals 4,984 5,720 Operating lease liability 2,588 3,088 Other 4,702 3,422 Total deferred tax assets 140,569 120,069 Less: Valuation allowance (138,214 ) (117,229 ) Net deferred tax assets 2,355 2,840 Deferred tax liabilities Right-of-use assets (2,355 ) (2,840 ) Total deferred tax liabilities (2,355 ) (2,840 ) Net deferred tax assets $ — $ —
Schedule of Unrecognized Tax Benefits	At December 31, 2020 and 2019, the Company’s unrecognized tax benefits consist of the following (in thousands): Year Ended December 31, 2020 2019 Unrecognized tax benefit, beginning of period $ 2,158 $ 1,595 Gross increases — current year tax positions 548 595 Gross increases — prior year tax positions — — Gross decreases — prior year tax positions (25 ) (32 ) Unrecognized tax benefit, end of period $ 2,681 $ 2,158

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Computation of Company's Basic and Diluted Net Loss Per Share	The following table sets forth the computation of the Company’s basic and diluted net loss per share for the periods presented (in thousands, except share and per share data): Year Ended December 31, 2020 2019 2018 Net loss attributable to common stockholders, basic and diluted $ (107,908 ) $ (120,199 ) $ (79,124 ) Weighted-average common shares used in computing net loss per share, basic and diluted 147,895,561 102,001,954 81,123,140 Net loss per share, basic and diluted $ (0.73 ) $ (1.18 ) $ (0.98 )
Dilutive Securities Excluded from Calculation of Diluted Earnings Per Share	The following table sets forth securities outstanding that could potentially dilute the calculation of diluted earnings per share: Year Ended December 31, 2020 2019 2018 Options to purchase common stock 8,142,348 11,165,846 11,603,708 Warrants to purchase common stock - liability classified 2,156,153 2,156,153 2,840,147 Warrants to purchase common stock - equity classified 1,418,116 1,457,866 1,586,097 Unvested restricted stock units 8,046,399 4,379,777 1,736,234

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Summary of Revenue by Geographic Area Based on the Shipping Address of the Customers' Location	The following table sets forth revenue by geographic area based on the shipping address of the customers’ location (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 16,167 $ 46,236 $ 34,231 Taiwan 10,710 — 4,680 France 7,025 12,235 5,812 United Kingdom 6,060 5,974 — Germany 839 7,393 13,727 Rest of world 16,216 15,944 22,512 Total revenue $ 57,017 $ 87,782 $ 80,962

Background and Organization - A

Background and Organization - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jan. 07, 2021	Jan. 04, 2021	Dec. 06, 2019	Dec. 03, 2019	Aug. 17, 2018	Aug. 14, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Net loss							$ (107,908)	$ (120,199)	$ (76,396)
Net cash used in operations							(63,474)	(79,567)	$ (122,194)
Cash and cash equivalents							$ 156,720	$ 226,783
Underwriters | Common Stock
Organization And Nature Of Operations [Line Items]
Underwriting agreement date				Dec. 3, 2019		Aug. 14, 2018
Number of shares issued in transaction				41,550,000		16,216,217
Sale of stock, price				$ 3.13		$ 9.25
Aggregate proceeds from issuance of common stock			$ 138,400		$ 161,900
Underwriters | Common Stock | Subsequent Event
Organization And Nature Of Operations [Line Items]
Underwriting agreement date		Jan. 4, 2021
Number of shares issued in transaction		11,856,500
Sale of stock, price		$ 4.85
Aggregate proceeds from issuance of common stock	$ 53,500

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Significant Accounting Policies [Line Items]
Restricted cash	$ 1,460,000	$ 1,404,000
Allowance for doubtful accounts	0	0
Inventory lower of cost and net realizable value adjustment	150,000	0	$ 340,000
Asset retirement obligation	900,000
Impairment loss recognized	$ 0	0	0
Service contract term	12 months
Capitalized costs associated with development of software	$ 0
Deferred commission	2,400,000	2,100,000
Penalties and interest related to income taxes	$ 0
Change in Accounting Principle, Accounting Standards Update, Adopted	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 1, 2020
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect	true
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201813Member
Asset Retirement Obligation
Significant Accounting Policies [Line Items]
Accretion expenses	$ 63,000	43,000	$ 33,000
Software
Significant Accounting Policies [Line Items]
Property and equipment, useful life	3 years
Minimum
Significant Accounting Policies [Line Items]
Property and equipment, useful life	2 years
Maximum
Significant Accounting Policies [Line Items]
Property and equipment, useful life	15 years
Irrevocable Standby Letters of Credit
Significant Accounting Policies [Line Items]
Letters of credit drawn, amount	$ 0	0
Collateral for Letters of Credit
Significant Accounting Policies [Line Items]
Restricted cash	$ 1,400,000	900,000
Collateral For Credit Card
Significant Accounting Policies [Line Items]
Restricted cash		$ 500,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Customers Representing Greater than 10% of Accounts Receivable and Revenue (Detail) - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue | Customer A
Concentration Risk [Line Items]
Percentage of concentration risk	11.00%
Revenue | Customer C
Concentration Risk [Line Items]
Percentage of concentration risk	10.00%
Revenue | Customer G
Concentration Risk [Line Items]
Percentage of concentration risk	19.00%
Revenue | Customer H
Concentration Risk [Line Items]
Percentage of concentration risk	12.00%	14.00%
Accounts Receivable | Customer A
Concentration Risk [Line Items]
Percentage of concentration risk	30.00%
Accounts Receivable | Customer B
Concentration Risk [Line Items]
Percentage of concentration risk	25.00%
Accounts Receivable | Customer C
Concentration Risk [Line Items]
Percentage of concentration risk	20.00%
Accounts Receivable | Customer D
Concentration Risk [Line Items]
Percentage of concentration risk		34.00%
Accounts Receivable | Customer E
Concentration Risk [Line Items]
Percentage of concentration risk		25.00%
Accounts Receivable | Customer F
Concentration Risk [Line Items]
Percentage of concentration risk		15.00%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Depreciation and Amortization Periods for Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2020
Minimum
Property Plant And Equipment [Line Items]
Property and equipment, useful life	2 years
Maximum
Property Plant And Equipment [Line Items]
Property and equipment, useful life	15 years
Prototype | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, useful life	2 years
Prototype | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, useful life	10 years
Machinery and Equipment | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, useful life	3 years
Machinery and Equipment | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, useful life	15 years
Furniture and Fixtures | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, useful life	5 years
Furniture and Fixtures | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, useful life	10 years
Software
Property Plant And Equipment [Line Items]
Property and equipment, useful life	3 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and Equipment, Estimated Useful Life	Lesser of estimated useful life or remaining lease term

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 52,563	$ 45,802
Less: accumulated depreciation and amortization	(28,501)	(22,403)
Property and equipment, net	24,062	23,399
Prototype
Property Plant And Equipment [Line Items]
Property and equipment, gross	17,711	16,419
Machine and Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	17,486	15,816
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	14,196	6,718
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,295	1,284
Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,389	1,389
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 486	$ 4,176

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Depreciation and amortization	$ 6.4	$ 4.7	$ 3.4

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued payroll and related benefits	$ 12,810	$ 9,577
Accrued accounts payable	2,810	4,764
Payroll withholding tax, sales and other tax payable	1,398	1,066
Accrued legal and accounting	305	1,175
Product upgrade reserve	1,500	3,794
Other	458	1,014
Total accrued liabilities	$ 19,281	$ 21,390

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Deferred Revenue (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Revenue [Line Items]
Total deferred revenue	$ 12,666	$ 14,010
Less: current portion of deferred revenue	(10,094)	(10,457)
Noncurrent portion of deferred revenue	2,572	3,553
Product
Deferred Revenue [Line Items]
Total deferred revenue	1,888	3,141
Service
Deferred Revenue [Line Items]
Total deferred revenue	8,857	8,473
Distribution Rights
Deferred Revenue [Line Items]
Total deferred revenue	$ 1,921	$ 2,396

Balance Sheet Components - Sc_4

Balance Sheet Components - Schedule of Other Long Term Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued interest, noncurrent portion	$ 99	$ 516
Asset retirement obligation	857	861
Total other-long term liabilities	$ 956	$ 1,377

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Warrants exercised		683,994
Change in fair value of Level 3 financial liabilities	$ 509,000	$ 2,496,000	$ 9,379,000
2016 and 2017 Private Placement Warrants
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Warrants exercised	0	683,994
Aggregate fair value of warrants upon exercise		$ 4,000,000
Change in fair value of Level 3 financial liabilities	$ 500,000	2,500,000	9,400,000
Transfers between Level 1 to Level 2	0	0	0
Transfers between Level 2 to Level 1	0	0	0
Transfers into or out of Level 3	$ 0	$ 0	$ 0

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Schedule of Fair Value of Financial Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	$ 4,864	$ 5,373
Fair Value Measurement on Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	4,864	5,373
Fair Value Measurement on Recurring Basis | 2017 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	3,675	4,043
Fair Value Measurement on Recurring Basis | 2016 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	1,189	1,330
Fair Value Measurement on Recurring Basis | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	0	0
Fair Value Measurement on Recurring Basis | Level 1 | 2017 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	0	0
Fair Value Measurement on Recurring Basis | Level 1 | 2016 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	0	0
Fair Value Measurement on Recurring Basis | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	0	0
Fair Value Measurement on Recurring Basis | Level 2 | 2017 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	0	0
Fair Value Measurement on Recurring Basis | Level 2 | 2016 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	0	0
Fair Value Measurement on Recurring Basis | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	4,864	5,373
Fair Value Measurement on Recurring Basis | Level 3 | 2017 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	3,675	4,043
Fair Value Measurement on Recurring Basis | Level 3 | 2016 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Warrant Liability	$ 1,189	$ 1,330

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Summary of Changes in Fair Value of Level 3 Financial Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value, beginning of period	$ 5,373	$ 11,844	$ 22,420
Change in fair value of Level 3 financial liabilities	(509)	(2,496)	(9,379)
Fair value, end of period	4,864	5,373	11,844
2016 Placement Warrants
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of Placement Warrants at exercise	0	(3,457)	(1,187)
2017 Placement Warrants
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of Placement Warrants at exercise	$ 0	$ (518)	$ (10)

Debt - Additional Information (

Debt - Additional Information (Detail) $ in Thousands	Oct. 30, 2020USD ($)Installment	Oct. 29, 2020USD ($)	Dec. 30, 2019	Dec. 31, 2018USD ($)Installment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Debt extinguishment loss					$ 0	$ 0	$ 2,416
Proceeds from term loan					$ 0	$ 0	56,000
SVB Term Loan
Debt Instrument [Line Items]
Total principal amount	$ 58,000	$ 56,000		$ 56,000			$ 56,000
Debt maturity date	Oct. 1, 2025			Dec. 1, 2023
Debt instrument interest rate percentage		6.30%		6.30%			6.30%
Frequency of periodic payment	monthly			monthly
Number of installments | Installment	36			36
Number of installments if achieving trailing revenue target and company so elects | Installment				30
Debt instrument description	revise the thirty-six equal monthly payments of principal to begin on November 1, 2022				Beginning on December 1, 2020 (or June 1, 2021, if the Company achieves a trailing twelve-month revenue of at least a specified amount and elects to apply such later date), the Company would have made thirty-six equal monthly payments of principal (or thirty equal payments, if the Company so elects).
Final payment percentage of original principal amount	3.70%	3.15%		3.15%			3.15%
Proceeds from term loan							$ 55,400
Legal and consulting fees							$ 600
Debt instrument first amendment terms					The First Amendment, among other things, amended the SVB Term Loan to (i) suspend testing of the minimum revenue financial covenant for the fiscal quarter ending December 31, 2019, (ii) provide for the minimum trailing twelve-month revenue thresholds under the minimum revenue financial covenant for periods ending on the last day of fiscal quarters in fiscal years subsequent to 2020 to be determined annually at the greater of (a) a 25% cushion to revenue forecasts provided by the Company to SVB and (b) 10% year-over-year annual growth, unless otherwise agreed, (iii) increase the minimum liquidity ratio financial covenant from 1.50:1.00 to 1.75:1.00 and (iv) increase the prepayment premium from 1.00% to 2.00% for amounts prepaid under the SVB Term Loan for prior to the maturity date thereof, subject to certain exceptions.
Debt instrument minimum liquidity ratio financial covenant	170.00%	175.00%	150.00%			175.00%
Debt instrument prepayment premium percentage	3.00%	2.00%	1.00%			2.00%
Debt instrument second amendment terms					The Second Amendment, among other things, amended the SVB Term Loan to (i) increase the term loan agreement principal amount from $56.0 million to $58.0 million, (ii) revise the thirty-six equal monthly payments of principal to begin on November 1, 2022, (iii) revise the maturity date to October 1, 2025, (iv) decrease the interest rate from a fixed rate of 6.3% to a floating rate of 2.4% above the Prime Rate, (v) increase the final payment from 3.15% of the original aggregate principal amount to 3.7% of the revised aggregate principal amount, (vi) revise the minimum trailing twelve-month revenue thresholds under the minimum revenue financial covenant for periods ending on the last day of fiscal quarters in fiscal years subsequent to 2020, (vii) decrease the minimum liquidity ratio financial covenant from 1.75:1.00 to 1.70:1.00, (viii) remove the minimum cash balance as a condition of the minimum revenue financial covenant and the minimum liquidity ratio financial covenant, and (ix) increase the prepayment premium from 2.00% to 3.00% for the first 30 months of the term for amounts prepaid under the SVB Term Loan prior to the maturity date thereof, subject to certain exceptions.
Minimum trailing period for revenue thresholds under minimum revenue financial covenant	12 months
Debt instrument final payment	$ 800
SVB Term Loan | Prime Rate
Debt Instrument [Line Items]
Debt instrument floating rate	2.40%
CRG Term Loan
Debt Instrument [Line Items]
Debt extinguishment loss					$ 2,400
Write-off of unamortized debt discount and debt issuance costs					$ 300

Debt - Scheduled Future Payment

Debt - Scheduled Future Payments on Term Loan (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Less: current portion	$ 0	$ (1,556)
Long-term portion	56,940	$ 53,995
SVB Term Loan
Debt Instrument [Line Items]
2021	0
2022	3,222
2023	19,333
2024	19,333
2025	16,112
Total future principal payments	58,000
Less: unamortized debt discount	(1,060)
Carrying value of long-term debt	56,940
Less: current portion	0
Long-term portion	$ 56,940

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Mar. 03, 2021ft²	Sep. 10, 2019Patent	Apr. 30, 2018ft²	Dec. 31, 2020USD ($)ft²	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Operating Leased Assets [Line Items]
Weighted-average remaining lease term				4 years 8 months 12 days
Weighted-average discount rate				7.70%
Operating lease cost | $				$ 3.1	$ 2.9
Rent expense | $						$ 1.4
Number of patents infringes | Patent		2
Purchase commitments | $				$ 2.3
Lease Agreement | Oakwood Village, Ohio
Operating Leased Assets [Line Items]
Area of land				19,800
Lease agreement, expiration date				2026-10
Lease Agreement | Mountain View, California
Operating Leased Assets [Line Items]
Area of land			24,600	25,500
Lease agreement, expiration date			2025-12	2025-07
Lease Agreement | Mountain View, California | Maximum
Operating Leased Assets [Line Items]
Lease agreement, renewal term			5 years
Sub-Lease Agreement | Denver, Colorado
Operating Leased Assets [Line Items]
Area of land				19,800
Lease agreement, expiration date				2021-07
Lease commencement date				2019-06
Sub-Lease Agreement | Denver, Colorado | Subsequent Event
Operating Leased Assets [Line Items]
Area of land	12,800
Lease commencement date	Sep. 1, 2021
Lease agreement, expiration date	Oct. 31, 2024

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Cash Flow Transactions Arising From Lease Transactions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 3,145	$ 2,451
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 643	$ 1,647	$ 0

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Future Minimum Payments and Interest Expense for Operating Leases (Detail) $ in Thousands	Dec. 31, 2020USD ($)
Operating Lease Liabilities Payments Due [Abstract]
2021	$ 2,847
2022	2,659
2023	2,738
2024	2,774
2025	2,096
Thereafter	147
Total undiscounted cash flows	13,261
Less: imputed interest	(2,129)
Present value of lease liabilities	$ 11,132

Revenue - Summary of Revenue Di

Revenue - Summary of Revenue Disaggregated by Types and Geography (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	$ 57,017	$ 87,782	$ 80,962
Product
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	42,742	79,504	76,626
Service
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	13,800	7,803	3,861
Distribution Rights
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	475	475	475
U.S.
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	16,167	46,236	34,231
U.S. | Product
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	8,428	41,985	32,265
U.S. | Service
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	7,739	4,251	1,966
Outside of U.S. ("OUS")
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	40,850	41,546	46,731
Outside of U.S. ("OUS") | Product
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	34,314	37,519	44,361
Outside of U.S. ("OUS") | Service
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	6,061	3,552	1,895
Outside of U.S. ("OUS") | Distribution Rights
Disaggregation Of Revenue [Line Items]
Product, service and distribution rights revenue	$ 475	$ 475	$ 475

Revenue - Additional Informatio

Revenue - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Aug. 31, 2016	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2014
Revenues [Line Items]
Long-term trade receivables		$ 100,000	$ 200,000
Long-term trade credit maintenance services term		1 year
Allowance for doubtful accounts		$ 0	0
Deferred revenue, recognized		$ 8,300,000	10,900,000	$ 19,900,000
Company recognized revenue from performance obligations satisfied in a prior period			$ 900,000
Minimum
Revenues [Line Items]
Expected long-term trade receivables collection period		3 years
Maximum
Revenues [Line Items]
Expected long-term trade receivables collection period		4 years
Itochu Corporation Agreement
Revenues [Line Items]
Remaining term of distribution agreement	8 years 6 months
Itochu Corporation Agreement | Distribution Rights
Revenues [Line Items]
Distribution revenue reclassified as deferred revenue					$ 4,000,000
Remaining term of distribution agreement	8 years 6 months

Licensing Agreement- Additional

Licensing Agreement- Additional Information (Detail) - Licensing Agreements - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2004	Mar. 31, 2014	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Licenses Agreements [Line Items]
Common Stock granted in exchange for licensing	33,652
Milestone description			ViewRay Technologies, Inc. met all of the product development and commercialization milestones at December 31, 2013, and started to make quarterly royalty payments in 2014.
Percentage of royalty payment based on net sale			1.00%
Cost of Sales
Licenses Agreements [Line Items]
Royalty Expense			$ 700,000	$ 1,000,000	$ 600,000
General and Administrative
Licenses Agreements [Line Items]
Royalty Expense			$ 0	$ 0	$ 30,000
Minimum
Licenses Agreements [Line Items]
Royalty payment per quarter		$ 50,000

Distribution Agreement - Additi

Distribution Agreement - Additional Information (Detail) - Itochu Corporation Agreement $ in Millions	1 Months Ended		12 Months Ended			24 Months Ended
	Aug. 31, 2016USD ($)	Dec. 31, 2014USD ($)Installment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2015USD ($)
Distribution Agreement [Line Items]
Distribution agreement term		10 years
Distribution fees			$ 0.5	$ 0.5	$ 0.5
Number of installments | Installment		3
Remaining term of distribution agreement	8 years 6 months
Distribution Rights
Distribution Agreement [Line Items]
Distribution fees		$ 4
Distribution fee reclassified to deferred revenue	$ 4
Distribution Rights | First Installment
Distribution Agreement [Line Items]
Distribution fees		1
Distribution Rights | Second Installment
Distribution Agreement [Line Items]
Distribution fees		1
Distribution Rights | Third Installment
Distribution Agreement [Line Items]
Distribution fees		$ 2
Distribution fees payment	$ 2
Distribution Rights | First and Second Installment
Distribution Agreement [Line Items]
Distribution fees payment						$ 2

Equity Financing - Additional I

Equity Financing - Additional Information (Detail) - USD ($)

Jan. 07, 2021

Jan. 04, 2021

Dec. 06, 2019

Dec. 03, 2019

Aug. 17, 2018

Aug. 14, 2018

Feb. 28, 2018

Jan. 31, 2017

Sep. 30, 2016

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Jan. 31, 2019

Apr. 19, 2018

Apr. 30, 2017

Subsidiary Sale Of Stock [Line Items]

Proceed from private placement and equity issuances, gross

$ 26,100,000

$ 13,800,000

Preferred stock conversion rate

100.00%

Underwriters | Common Stock

Subsidiary Sale Of Stock [Line Items]

Underwriting agreement date

Dec. 3, 2019

Aug. 14, 2018

Number of shares issued in transaction

41,550,000

16,216,217

Sale of stock, price

$ 3.13

$ 9.25

Option to purchase additional shares

30 days

30 days

Aggregate proceeds from issuance of common stock

$ 138,400,000

$ 161,900,000

Underwriters | Common Stock | Subsequent Event

Subsidiary Sale Of Stock [Line Items]

Underwriting agreement date

Jan. 4, 2021

Number of shares issued in transaction

11,856,500

Sale of stock, price

$ 4.85

Aggregate proceeds from issuance of common stock

$ 53,500,000

Underwriters | Common Stock | Maximum

Subsidiary Sale Of Stock [Line Items]

Number of additional shares issued in transaction

6,232,500

2,432,432

March 2018 Direct Registered Offering

Subsidiary Sale Of Stock [Line Items]

Proceed from private placement and equity issuances, gross

$ 59,100,000

March 2018 Direct Registered Offering | Common Stock

Subsidiary Sale Of Stock [Line Items]

Stock issued during period

4,090,000

March 2018 Direct Registered Offering | Series A Convertible Preferred Stock

Subsidiary Sale Of Stock [Line Items]

Stock issued during period

3,000,581

March 2018 Direct Registered Offering Warrants

Subsidiary Sale Of Stock [Line Items]

Warrants to purchase common stock, shares

1,418,116

Warrant exercise price

$ 8.31

Warrant expiration date

2025-03

At The Market Offering Program January and April 2017 | Maximum

Subsidiary Sale Of Stock [Line Items]

Maximum common stock saleable shares, value

$ 50,000,000

At The Market Offering Program January and April 2017 | Common Stock

Subsidiary Sale Of Stock [Line Items]

Aggregate proceeds from issuance of common stock

$ 300,000

Stock issued during period

33,097

Average market price per share

$ 8.41

At The Market Offering Program January 2019 | Maximum

Subsidiary Sale Of Stock [Line Items]

Maximum common stock saleable shares, value

$ 100,000,000

Maximum aggregate offering price

$ 250,000,000

At The Market Offering Program January 2019 | Common Stock

Subsidiary Sale Of Stock [Line Items]

Stock issued during period

0

0

At The Market Offering Program January 2021 | Subsequent Event

Subsidiary Sale Of Stock [Line Items]

Maximum common stock saleable shares, value

$ 42,900,000

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Apr. 19, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Convertible Preferred Stock [Line Items]
Preferred stock conversion rate	100.00%
Convertible preferred stock, shares outstanding			0	0
Series A Convertible Preferred Stock | 2018 Direct Registered Offering
Convertible Preferred Stock [Line Items]
Convertible preferred stock, shares issued		3,000,581
Stock price		$ 8.31
Convertible preferred stock, beneficial conversion feature		$ 2.7
Number of preferred stock converted into common stock	3,000,581

Warrants - Additional Informati

Warrants - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended				3 Months Ended	12 Months Ended
	Jan. 31, 2017	Sep. 30, 2016	Aug. 31, 2015	Jul. 31, 2015	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2013
Common Stock Warrants [Line Items]
Placement warrants not exercised and remained outstanding						2,156,153	2,156,153
Proceed from private placement and equity issuances, gross	$ 26,100	$ 13,800
Fair value of warrants upon issuance	$ 3,400	$ 2,700
Change in fair value of warrant liability						$ (509)	$ (2,496)	$ (9,379)
2018 Direct Registered Offering | Common Stock
Common Stock Warrants [Line Items]
Warrants issued					1,418,116
Exercise price					$ 8.31
Common stock warrants, expiration date					Mar. 31, 2025
Number of warrant exercised						0
Proceed from private placement and equity issuances, gross					$ 59,100
Fair value of warrants upon issuance					7,400
Allocated portion of proceeds from issuance of stock and warrants recorded in additional paid-in-capital					$ 6,600
2013 Placement Warrants
Common Stock Warrants [Line Items]
Warrants issued									128,231
Exercise price									$ 5.84
Common stock warrants, expiration date						Dec. 16, 2023
Stock issued during period							36,457
Number of warrant exercised							128,231
Placement warrants not exercised and remained outstanding						0
2015 Placement Warrants
Common Stock Warrants [Line Items]
Warrants issued			198,760	198,760
Exercise price			$ 5	$ 5
Stock issued during period								92,487
Number of warrant exercised								159,010
Placement warrants not exercised and remained outstanding						0
Common stock warrants, expiry term			5 years	5 years
Number of warrant expired			39,750	39,750
2016 Placement Warrants
Common Stock Warrants [Line Items]
Warrants issued		1,380,745
Exercise price						$ 2.95
Placement warrants not exercised and remained outstanding						537,263	537,263
Common stock warrants, expiry term						7 years
2016 Placement Warrants | Common Stock
Common Stock Warrants [Line Items]
Change in fair value of warrant liability						$ (100)	$ 100	$ (4,000)
2017 Placement Warrants
Common Stock Warrants [Line Items]
Warrants issued	1,720,512
Exercise price						$ 3.17
Placement warrants not exercised and remained outstanding						1,618,890	1,618,890
Common stock warrants, expiry term						7 years
2017 Placement Warrants | Common Stock
Common Stock Warrants [Line Items]
Change in fair value of warrant liability						$ (400)	$ (2,600)	$ (5,400)

Warrants - Summary of Assumptio

Warrants - Summary of Assumptions to Use Option Pricing Model (Detail)	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2018	Jan. 31, 2017	Sep. 30, 2016
Common Stock | 2018 Direct Registered Offering | Expected Term
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Expected term (in years)			7 years
Common Stock | 2018 Direct Registered Offering | Expected Volatility
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Warrants, fair value measurement inputs			0.625
Common Stock | 2018 Direct Registered Offering | Risk-free Interest Rate
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Warrants, fair value measurement inputs			0.028
Common Stock | 2018 Direct Registered Offering | Expected Dividend Yield
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Warrants, fair value measurement inputs			0
2017 Placement Warrants | Expected Term
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Expected term (in years)	3 years	4 years		7 years
2017 Placement Warrants | Expected Volatility
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Warrants, fair value measurement inputs	0.869	0.680		0.629
2017 Placement Warrants | Risk-free Interest Rate
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Warrants, fair value measurement inputs	0.002	0.017		0.022
2017 Placement Warrants | Expected Dividend Yield
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Warrants, fair value measurement inputs	0	0		0
2016 Placement Warrants | Expected Term
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Expected term (in years)	2 years 7 months 6 days	3 years 7 months 6 days			7 years
2016 Placement Warrants | Expected Volatility
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Warrants, fair value measurement inputs	0.863	0.675			0.616
2016 Placement Warrants | Risk-free Interest Rate
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Warrants, fair value measurement inputs	0.002	0.016			0.014
2016 Placement Warrants | Expected Dividend Yield
Fair Value Inputs1 Liabilities Quantitative Information [Line Items]
Warrants, fair value measurement inputs	0	0			0

Warrants - Schedule of Key Term

Warrants - Schedule of Key Terms of Placement Warrants (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Warrants Exercised		683,994
Warrants Outstanding	2,156,153	2,156,153
2017 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Issuance Date	2017-01
Term	7 years
Exercise Price Per Share	$ 3.17
Warrants Exercised		90,642
Warrants Outstanding	1,618,890	1,618,890
2016 Placement Warrants
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Issuance Date	2016-08
Issuance Date	2016-09
Term	7 years
Exercise Price Per Share	$ 2.95
Warrants Exercised		593,352
Warrants Outstanding	537,263	537,263

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	4 years
Weighted average grant date fair value of RSUs granted	$ 2.80
Weighted average period for recognition of compensation costs	2 years
Expiration period of stock option plan	10 years
Weighted average grant date fair value of options granted, per share	$ 1.20	$ 4.67	$ 4.89
Grant date fair value of options vested	$ 9,200,000	$ 14,400,000	$ 6,300,000
Aggregate intrinsic value of options exercised	0	7,800,000	17,700,000
Unrecognized compensation cost	10,100,000
Stock-based compensation expense	$ 22,805,000	$ 19,445,000	$ 14,169,000
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant date fair value of RSUs granted	$ 2.80	$ 3.63	$ 9.65
Total grant date fair value of RSUs	$ 17,000,000	$ 12,200,000	$ 17,000,000
Total fair value of RSUs vested	10,100,000	$ 6,000,000	300,000
Unrecognized stock based compensation cost	$ 17,400,000
Weighted average period for recognition of compensation costs	1 year 10 months 24 days
Shares expected to vest	7,700,000
Restricted Stock Units (RSUs) | Employees | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	3 years
Restricted Stock Units (RSUs) | Employees | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	2 years
2015 and 2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for grant	7,900,000
2015 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock based compensation cost	$ 0
Percentage of market value price of common stock under Employee Stock Purchase Plan	85.00%
Common stock reserved for issuance	3,500,000	2,700,000
Shares issued under ESPP	200,000
Common stock remained available for issuance pursuant to the purchase plan	3,300,000
Stock-based compensation expense	$ 100,000	$ 0	$ 0
2015 Employee Stock Purchase Plan | Offering Period
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum contribution percentage amount of employee's base compensation	15.00%
Maximum employee contribution in to share purchase plan per offering	$ 30,000
Number of common stock authorized for issuance	3,000
2015 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock authorized for issuance	3,500,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 22,805	$ 19,445	$ 14,169
Cost of Revenue
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	965	2,645	1,609
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,288	3,910	2,681
Selling and Marketing
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,091	1,365	736
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 18,461	$ 11,525	$ 9,143

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of RSU Activity (Detail)	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Unvested at December 31, 2019, Number of Shares	4,379,777
RSUs granted, Number of Shares	6,079,659
RSUs vested, Number of Shares	(1,779,152)
RSUs cancelled or forfeited, Number of Shares	(633,885)
Unvested at December 31, 2020, Number of Shares	8,046,399
Vested and unreleased, Number of Shares	177,007
Outstanding at December 31 2020, Number of Shares	8,223,406
Unvested at December 31, 2019, Weighted Average Grant Date Fair Value | $ / shares	$ 5.14
RSUs granted, Weighted Average Grant Date Fair Value | $ / shares	2.80
RSUs vested, Weighted Average Grant Date Fair Value | $ / shares	5.69
RSUs cancelled or forfeited, Weighted Average Grant Date Fair Value | $ / shares	3.11
Unvested at December 31, 2020, Weighted Average Grant Date Fair Value | $ / shares	$ 3.41

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Company's Stock Option Activity and Related Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of Stock Options Outstanding
Number of Stock Options Outstanding, Beginning balance	11,165,846
Number of Stock Options Outstanding, Options granted	736,579
Number of Stock Options Outstanding, Options exercised	(20,579)
Number of Stock Options Outstanding, Options cancelled or forfeited	(3,739,498)
Number of Stock Options Outstanding, Ending balance	8,142,348	11,165,846
Number of Stock Options Outstanding, Options exercisable	5,319,817
Number of Stock Options Outstanding, Options vested and expected to vest	7,875,294
Weighted- Average Exercise Price
Weighted- Average Exercise Price, Beginning balance	$ 7.44
Weighted- Average Exercise Price, Options granted	1.97
Weighted- Average Exercise Price, Options exercised	0.72
Weighted- Average Exercise Price, Options cancelled or forfeited	6.95
Weighted- Average Exercise Price, Ending balance	7.14	$ 7.44
Weighted- Average Exercise Price, Options exercisable	7.20
Weighted- Average Exercise Price,Options vested and expected to vest	$ 7.18
Weighted- Average Remaining Contractual Life (Years)
Options Outstanding, Weighted- Average Remaining Contractual Life (Years)	7 years 3 months 18 days	7 years 7 months 6 days
Weighted- Average Remaining Contractual Life (Years), Options exercisable	6 years 9 months 18 days
Weighted- Average Remaining Contractual Life (Years), Options vested and expected to vest	7 years 2 months 12 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value	$ 2,638	$ 1,907
Aggregate Intrinsic Value, Options exercisable	1,354
Aggregate Intrinsic Value, Options vested and expected to vest	$ 2,438

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Weighted-Average Assumptions Used in Black-Scholes Option-Pricing Model to Estimate Fair Value of Employee Stock Options/Purchases at Grant Date (Detail)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years	6 years	6 years
Expected volatility (%)	68.80%	60.70%	60.40%
Risk-free interest rate (%)	0.70%	2.40%	2.80%
Expected dividend yield (%)	0.00%	0.00%	0.00%
2015 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility (%)	83.00%
Expected dividend yield (%)	0.00%
Risk-free interest rate (%), Minimum	0.09%
Risk-free interest rate (%), Maximum	0.17%
2015 Employee Stock Purchase Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	3 months
2015 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 months

Income Taxes - Income Tax Recon

Income Taxes - Income Tax Reconciliation (Detail)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Abstract]
Expected income tax benefit at the federal statutory rate	21.00%	21.00%	21.00%
State taxes, net of federal benefit	0.00%	0.00%	0.00%
Change in federal statutory rate	0.00%	0.00%	0.00%
Non-deductible items and other	(3.40%)	(2.80%)	(0.20%)
Federal and state credits	0.50%	0.60%	0.70%
Change in valuation allowance	(18.10%)	(18.80%)	(21.50%)
Total	0.00%	0.00%	0.00%

Income Taxes - Deferred Income

Income Taxes - Deferred Income Tax (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets
Net operating loss carryforwards	$ 121,346	$ 101,967
Research and development tax credits	6,949	5,872
Reserves and accruals	4,984	5,720
Operating lease liability	2,588	3,088
Other	4,702	3,422
Total deferred tax assets	140,569	120,069
Less: Valuation allowance	(138,214)	(117,229)
Net deferred tax assets	2,355	2,840
Deferred tax liabilities
Right-of-use assets	(2,355)	(2,840)
Total deferred tax liabilities	(2,355)	(2,840)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Taxes [Line Items]
Deferred Tax Valuation allowance increase (decrease)	$ 21	$ 25.2
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 527.1
Operating loss carryforwards, expiration date	Dec. 31, 2024
Federal [Member] | Research Tax Credit Carryforward
Income Taxes [Line Items]
Tax credit carryforwards	$ 6.3
Tax credit carryforwards, expiration date	Dec. 31, 2027
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 303.4
Operating loss carryforwards, expiration date	Dec. 31, 2020
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward
Income Taxes [Line Items]
Tax credit carryforwards	$ 3.9
Tax credit carryforwards, expiration date	Dec. 31, 2027

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefit, beginning of period	$ 2,158	$ 1,595
Gross increases — current year tax positions	548	595
Gross increases — prior year tax positions	0	0
Gross decreases — prior year tax positions	(25)	(32)
Unrecognized tax benefit, end of period	$ 2,681	$ 2,158

Employee Benefits - Additional

Employee Benefits - Additional information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan Disclosure [Line Items]
Description of defined contribution plan	The Company has a 401(k) Plan which covers its eligible employees. The 401(k) Plan permits the participants to defer a portion of their compensation in accordance with the provisions of Section 401(k) of the IRC. Participant contributions are limited to a maximum annual amount as set periodically by the IRC.
Employer matching contribution	50.00%
Matching contribution to 401(k) plan	$ 1.1	$ 0.9	$ 0.5
Maximum
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution percent of eligible compensation	6.00%

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of Company's Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net loss attributable to common stockholders, basic and diluted	$ (107,908)	$ (120,199)	$ (79,124)
Weighted-average common shares used in computing net loss per share, basic and diluted	147,895,561	102,001,954	81,123,140
Net loss per share, basic and diluted	$ (0.73)	$ (1.18)	$ (0.98)

Net Loss Per Share - Dilutive S

Net Loss Per Share - Dilutive Securities Excluded from Calculation of Diluted Earnings Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Options To Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Dilutive securities excluded from calculation of diluted earnings per share	8,142,348	11,165,846	11,603,708
Warrants To Purchase Common Stock - Liability Classified
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Dilutive securities excluded from calculation of diluted earnings per share	2,156,153	2,156,153	2,840,147
Warrants To Purchase Common Stock - Equity Classified
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Dilutive securities excluded from calculation of diluted earnings per share	1,418,116	1,457,866	1,586,097
Unvested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Dilutive securities excluded from calculation of diluted earnings per share	8,046,399	4,379,777	1,736,234

Net Loss Per Share - Additional

Net Loss Per Share - Additional Information (Detail) - Underwriters - Common Stock - $ / shares	Jan. 04, 2021	Dec. 03, 2019	Aug. 14, 2018
Earnings Per Share [Line Items]
Underwriting agreement date		Dec. 3, 2019	Aug. 14, 2018
Number of shares issued in transaction		41,550,000	16,216,217
Sale of stock, price		$ 3.13	$ 9.25
Subsequent Event
Earnings Per Share [Line Items]
Underwriting agreement date	Jan. 4, 2021
Number of shares issued in transaction	11,856,500
Sale of stock, price	$ 4.85

Segment and Geographic Inform_3

Segment and Geographic Information - Additional Information (Detail) - Segment	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Number of reportable segments	1
Reportable Geographical Components | United States
Segment Reporting Information [Line Items]
Location of long-lived assets description	nearly all long-lived assets are located in the United States	nearly all long-lived assets are located in the United States

Segment and Geographic Inform_4

Segment and Geographic Information - Summary of Revenue by Geographic Area Based on the Shipping Address of the Customers' Location (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Entity Wide Revenue Major Customer [Line Items]
Total revenue	$ 57,017	$ 87,782	$ 80,962
United States
Entity Wide Revenue Major Customer [Line Items]
Total revenue	16,167	46,236	34,231
Reportable Geographical Components | United States
Entity Wide Revenue Major Customer [Line Items]
Total revenue	16,167	46,236	34,231
Reportable Geographical Components | Taiwan
Entity Wide Revenue Major Customer [Line Items]
Total revenue	10,710	0	4,680
Reportable Geographical Components | France
Entity Wide Revenue Major Customer [Line Items]
Total revenue	7,025	12,235	5,812
Reportable Geographical Components | United Kingdom
Entity Wide Revenue Major Customer [Line Items]
Total revenue	6,060	5,974	0
Reportable Geographical Components | Germany
Entity Wide Revenue Major Customer [Line Items]
Total revenue	839	7,393	13,727
Reportable Geographical Components | Rest of World
Entity Wide Revenue Major Customer [Line Items]
Total revenue	$ 16,216	$ 15,944	$ 22,512

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - Chindex Shanghai International Trading Company Limited $ in Millions	Nov. 29, 2019USD ($)Installment
Related Party Transaction [Line Items]
Distribution agreement term	5 years
Distribution agreement additional term	5 years
Number of installments | Installment	3
Upfront Fees
Related Party Transaction [Line Items]
Distribution fees	$ 3.5
Upfront Fees | First Installment
Related Party Transaction [Line Items]
Distribution fees	1.5
Upfront Fees | Second Installment
Related Party Transaction [Line Items]
Distribution fees	1
Upfront Fees | Third Installment
Related Party Transaction [Line Items]
Distribution fees	$ 1

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Sub-Lease Agreement - Denver, Colorado - ft²	Mar. 03, 2021	Dec. 31, 2020
Subsequent Event [Line Items]
Area of land		19,800
Subsequent Event
Subsequent Event [Line Items]
Area of land	12,800
Lease commencement date	Sep. 1, 2021
Lease agreement, expiration date	Oct. 31, 2024