Document and Entity Information
Document and Entity Information - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Feb. 14, 2018 | Jun. 30, 2017 | |
Document And Entity Information [Abstract] | |||
Document Type | 10-K | ||
Amendment Flag | false | ||
Document Period End Date | Dec. 31, 2017 | ||
Document Fiscal Year Focus | 2,017 | ||
Document Fiscal Period Focus | FY | ||
Trading Symbol | NVRO | ||
Entity Registrant Name | NEVRO CORP | ||
Entity Central Index Key | 1,444,380 | ||
Current Fiscal Year End Date | --12-31 | ||
Entity Well-known Seasoned Issuer | Yes | ||
Entity Current Reporting Status | Yes | ||
Entity Voluntary Filers | No | ||
Entity Filer Category | Large Accelerated Filer | ||
Entity Common Stock, Shares Outstanding | 29,837,041 | ||
Entity Public Float | $ 1,952 |
Consolidated Balance Sheets
Consolidated Balance Sheets - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Current assets | ||
Cash and cash equivalents | $ 42,845 | $ 41,406 |
Short-term investments | 226,467 | 234,951 |
Accounts receivable, net of allowance for doubtful accounts of $1,333 and $1,008 at December 31, 2017 and 2016, respectively | 67,287 | 52,818 |
Inventories | 98,119 | 85,221 |
Prepaid expenses and other current assets | 6,463 | 5,895 |
Total current assets | 441,181 | 420,291 |
Property and equipment, net | 8,819 | 7,132 |
Other assets | 3,250 | 2,354 |
Restricted cash | 806 | 806 |
Total assets | 454,056 | 430,583 |
Current liabilities | ||
Accounts payable | 18,492 | 16,162 |
Accrued liabilities | 39,390 | 26,028 |
Other current liabilities | 122 | 8 |
Total current liabilities | 58,004 | 42,198 |
Long-term debt | 145,019 | 138,140 |
Other long-term liabilities | 1,861 | 1,211 |
Total liabilities | 204,884 | 181,549 |
Commitments and contingencies (Note 5) | ||
Stockholders’ equity | ||
Preferred stock, $0.001 par value, 10,000,000 shares authorized at December 31, 2017 and 2016, respectively; zero shares issued and outstanding at December 31, 2017 and 2016, respectively | ||
Common stock, $0.001 par value, 290,000,000 shares authorized at December 31, 2017 and 2016, respectively; 29,737,561 and 28,886,862 shares issued and outstanding at December 31, 2017 and 2016, respectively | 30 | 29 |
Additional paid-in capital | 508,228 | 470,869 |
Accumulated other comprehensive loss | (1,242) | (678) |
Accumulated deficit | (257,844) | (221,186) |
Total stockholders’ equity | 249,172 | 249,034 |
Total liabilities and stockholders’ equity | $ 454,056 | $ 430,583 |
Consolidated Balance Sheets (Pa
Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Statement Of Financial Position [Abstract] | ||
Accounts receivable, allowance for doubtful accounts | $ 1,333 | $ 1,008 |
Preferred stock, par value | $ 0.001 | $ 0.001 |
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 | $ 0.001 | $ 0.001 |
Common stock, shares authorized | 290,000,000 | 290,000,000 |
Common stock, shares issued | 29,737,561 | 28,886,862 |
Common stock, shares outstanding | 29,737,561 | 28,886,862 |
Consolidated Statements of Oper
Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Statement [Abstract] | |||
Revenue | $ 326,674 | $ 228,504 | $ 69,606 |
Cost of revenue | 98,981 | 75,433 | 28,120 |
Gross profit | 227,693 | 153,071 | 41,486 |
Operating expenses | |||
Research and development | 37,560 | 33,729 | 21,382 |
Sales, general and administrative | 219,712 | 142,423 | 82,471 |
Total operating expenses | 257,272 | 176,152 | 103,853 |
Loss from operations | (29,579) | (23,081) | (62,367) |
Interest income | 3,164 | 1,685 | 575 |
Interest expense | (9,902) | (6,394) | (2,732) |
Other income (expense), net | 1,067 | (1,097) | (1,741) |
Loss on extinguishment of debt | (1,268) | ||
Loss before income taxes | (35,250) | (30,155) | (66,265) |
Provision for income taxes | 1,408 | 1,623 | 1,166 |
Net loss | (36,658) | (31,778) | (67,431) |
Other comprehensive loss: | |||
Changes in foreign currency translation adjustment | (360) | (163) | (178) |
Changes in unrealized losses on short-term investments, net | (204) | (340) | (74) |
Net change in other comprehensive loss | (564) | (503) | (252) |
Comprehensive loss | $ (37,222) | $ (32,281) | $ (67,683) |
Net loss per share, basic and diluted | $ (1.25) | $ (1.12) | $ (2.54) |
Weighted average number of common shares used to compute basic and diluted net loss per share | 29,424,054 | 28,485,003 | 26,581,890 |
Consolidated Statements of Stoc
Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands | Total | Common Stock [Member] | Additional Paid-In Capital [Member] | Accumulated Deficit [Member] | Accumulated Other Comprehensive Income (Loss) [Member] |
Beginning balances at Dec. 31, 2014 | $ 172,070 | $ 25 | $ 293,945 | $ (121,977) | $ 77 |
Beginning balances, shares at Dec. 31, 2014 | 24,865,491 | ||||
Issuance of common stock upon underwritten public offering, net of issuance costs | 118,439 | $ 3 | 118,436 | ||
Issuance of common stock upon underwritten public offering, shares | 2,470,587 | ||||
Exercise of common stock options | $ 2,958 | 2,958 | |||
Exercise of common stock options, shares | 751,610 | 774,337 | |||
Issuance of common stock under employee stock purchase plan | $ 1,430 | 1,430 | |||
Issuance of common stock under employee stock purchase plan, shares | 33,158 | ||||
Vesting of early exercised stock options | 53 | 53 | |||
Stock based compensation | 7,325 | 7,325 | |||
Net loss | (67,431) | (67,431) | |||
Other comprehensive loss | (252) | (252) | |||
Ending balances at Dec. 31, 2015 | 234,592 | $ 28 | 424,147 | (189,408) | (175) |
Ending balances, shares at Dec. 31, 2015 | 28,143,573 | ||||
Conversion feature of convertible senior notes due 2021, net of allocated costs | 31,767 | 31,767 | |||
Purchase of bond hedges | (45,092) | (45,092) | |||
Sales of warrants | 33,120 | 33,120 | |||
Exercise of common stock options | $ 6,808 | $ 1 | 6,807 | ||
Exercise of common stock options, shares | 667,494 | 669,337 | |||
Issuance of common stock upon release of restricted stock units | 1,384 | ||||
Issuance of common stock under employee stock purchase plan | $ 3,499 | 3,499 | |||
Issuance of common stock under employee stock purchase plan, shares | 72,568 | ||||
Vesting of early exercised stock options | 47 | 47 | |||
Stock based compensation | 15,760 | 15,760 | |||
Tax benefit from stock option deductions | 814 | 814 | |||
Net loss | (31,778) | (31,778) | |||
Other comprehensive loss | (503) | (503) | |||
Ending balances at Dec. 31, 2016 | 249,034 | $ 29 | 470,869 | (221,186) | (678) |
Ending balances, shares at Dec. 31, 2016 | 28,886,862 | ||||
Exercise of common stock options | $ 7,493 | $ 1 | 7,492 | ||
Exercise of common stock options, shares | 707,410 | 707,410 | |||
Issuance of common stock upon release of restricted stock units | 83,121 | ||||
Shares withheld for tax obligations | $ (991) | (991) | |||
Shares withheld for tax obligations, shares | (13,094) | ||||
Issuance of common stock under employee stock purchase plan | 4,697 | 4,697 | |||
Issuance of common stock under employee stock purchase plan, shares | 73,262 | ||||
Vesting of early exercised stock options | 7 | 7 | |||
Stock based compensation | 26,154 | 26,154 | |||
Net loss | (36,658) | (36,658) | |||
Other comprehensive loss | (564) | (564) | |||
Ending balances at Dec. 31, 2017 | $ 249,172 | $ 30 | $ 508,228 | $ (257,844) | $ (1,242) |
Ending balances, shares at Dec. 31, 2017 | 29,737,561 |
Consolidated Statements of Cash
Consolidated Statements of Cash Flows - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Cash flows from operating activities | |||
Net loss | $ (36,658) | $ (31,778) | $ (67,431) |
Adjustments to reconcile net loss to net cash used in operating activities | |||
Depreciation and amortization | 2,507 | 1,717 | 614 |
Stock-based compensation expense | 26,143 | 15,760 | 7,325 |
Accretion of discount on short-term investments | (116) | (231) | (458) |
Non-cash loss on extinguishment of debt | 1,156 | ||
Payment of original issue discount | (1,500) | ||
Provision for doubtful accounts | 293 | 909 | 90 |
Write-down of inventory | 3,984 | 4,056 | 2,767 |
Loss on disposal of equipment | 287 | ||
Non-cash interest expense | 6,884 | 3,681 | 231 |
Unrealized gains (losses) on foreign currency transactions | (799) | 1,854 | (682) |
Changes in operating assets and liabilities | |||
Accounts receivable | (13,899) | (32,181) | (16,233) |
Inventories | (16,297) | (27,031) | (49,407) |
Prepaid expenses and other current assets | (501) | (1,997) | (1,197) |
Other assets | (892) | (505) | (1,432) |
Accounts payable | 2,162 | (5,586) | 17,051 |
Accrued liabilities | 12,269 | 12,136 | 7,987 |
Other long-term liabilities | 647 | 750 | 345 |
Net cash used in operating activities | (14,273) | (58,503) | (100,430) |
Cash flows from investing activities | |||
Purchases of short-term investments | (287,938) | (372,309) | (190,000) |
Proceeds from sales of short-term investments | 5,993 | ||
Proceeds from maturity of short-term investments | 290,341 | 243,890 | 235,272 |
Changes in restricted cash | 100 | (606) | |
Purchases of property and equipment | (4,327) | (3,368) | (5,008) |
Net cash provided by (used in) investing activities | 4,069 | (131,687) | 39,658 |
Cash flows from financing activities | |||
Proceeds from issuance of common stock in public offering, net | 118,439 | ||
Proceeds from issuance of convertible notes | 172,500 | ||
Convertible notes initial issuance discount and debt issuance costs | (6,171) | ||
Proceeds from issuance of warrants | 33,120 | ||
Purchase of convertible note hedges | (45,092) | ||
Repayment of debt | (19,500) | ||
Minimum tax withholding paid on behalf of employees for net share settlement | (991) | ||
Proceeds from issuance of common stock to employees | 12,190 | 10,307 | 4,388 |
Net cash provided by financing activities | 11,199 | 145,164 | 122,827 |
Effect of exchange rate changes on cash and cash equivalents | 444 | (604) | (306) |
Net increase (decrease) in cash and cash equivalents | 1,439 | (45,630) | 61,749 |
Cash and cash equivalents | |||
Cash and cash equivalents at beginning of year | 41,406 | 87,036 | 25,287 |
Cash and cash equivalents at end of year | 42,845 | 41,406 | 87,036 |
Supplemental disclosures of cash flow information | |||
Cash paid for income taxes | 687 | 492 | 670 |
Cash paid for interest | 3,019 | 2,469 | 2,332 |
Significant non-cash transactions | |||
Purchases of property and equipment in accounts payable | 592 | 725 | 752 |
Vesting of early-exercised stock options | $ 7 | $ 47 | $ 53 |
Formation and Business of the C
Formation and Business of the Company | 12 Months Ended |
Dec. 31, 2017 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Formation and Business of the Company | 1. Formation and Business of the Company The Company was incorporated in Minnesota on March 10, 2006 to manufacture and market innovative active implantable medical devices for the treatment of neurological disorders initially focusing on the treatment of chronic pain. Subsequently, the Company was reincorporated in Delaware on October 4, 2006 and relocated to California. Since inception, the Company has incurred net losses and negative cash flows from operations. During the year ended December 31, 2017, the Company incurred a net loss of $36.7 million and used $14.3 million of cash in operations. At December 31, 2017, the Company had an accumulated deficit of $257.8 million and does not expect to experience positive cash flows in the immediate future. The Company has financed operations to date primarily through private placements of equity securities, borrowings under a debt agreement, the issuance of common stock in its November 2014 initial public offering and its June 2015 underwritten public offering, as well as its June 2016 underwritten public offering of convertible senior notes due in 2021. The Company’s ability to continue to meet its obligations and to achieve its business objectives for the foreseeable future is dependent upon, amongst other things, generating sufficient revenues and its ability to continue to control expenses to meet its obligations as they become due. Failure to increase sales of its products, manage discretionary expenditures or raise additional financing, if required, may adversely impact the Company’s ability to achieve its intended business objectives. Public Offerings In November 2014, the Company completed its initial public offering (IPO) of shares of its common stock and as a result, the following transactions were recorded in the Company’s consolidated financial statements during the fourth quarter of 2014: • the sale of 8,050,000 shares of common stock, including 1,050,000 from the exercise by the underwriters of their overallotment option, at an offering price of $18.00 per share, for net proceeds of $131.6 million, after deducting the underwriters’ discounts, commissions and offering costs paid by us; and • immediately prior to the completion of the IPO, all the outstanding shares of the Company’s redeemable convertible preferred stock and convertible preferred stock were converted into 15,208,048 shares of common stock. In June 2015, the Company completed an underwritten public offering of its common stock, which included shares of its common stock held by certain of its stockholders, and issued 2,470,587 shares of common stock, including 705,882 shares issued pursuant to the exercise in full by the underwriters of their option to purchase additional shares. The Company received cash proceeds of approximately $118.4 million, net of underwriting discounts and commissions and offering costs paid by the Company. In June 2016, the Company issued $150.0 million aggregate principal amount of 1.75% convertible senior notes due 2021 in a registered underwritten public offering and an additional $22.5 million aggregate principal amount of such notes pursuant to the exercise in full of the over-allotment options of the underwriters (the 2021 Notes). The interest rates are fixed at 1.75% per annum and are payable semi-annually in arrears on June 1 and December 1 of each year, commencing on December 1, 2016. The total net proceeds from the debt offering, after deducting transaction costs, were approximately $166.2 million. |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies Basis of Presentation These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the U.S. (U.S. GAAP). The consolidated financial statements include the Company’s accounts and those of its four wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated. Segments The chief operating decision maker for the Company is the Chief Executive Officer. The Chief Executive Officer reviews financial information presented on a consolidated basis, accompanied only by information about revenue by geographic region, for purposes of allocating resources and evaluating financial performance. The Company has one business activity and there are no segment managers who are held accountable for operations, operating results or plans for levels or components below the consolidated unit level, other than revenue. Accordingly, the Company has determined that it has a single reportable and operating segment structure. The Company and its Chief Executive Officer evaluate performance based primarily on revenue in the geographic locations in which the Company operates. Until 2015, the Company had derived most of its revenue from sales to customers in Australia and Europe. In May 2015, the U.S. Food and Drug Administration (FDA) approved the Company’s premarket approval (PMA) application to market Senza in the United States and the Company launched sales in the United States in 2015. Revenue by geography is based on the billing address of the customer. The following table sets forth revenue by geographic area for countries with revenue accounting for 10% of more of the total revenue during the periods presented: Years Ended December 31, 2017 2016 2015 United States 81 % 76 % 35 % Australia * * 20 % United Kingdom * * 12 % Germany * * 13 % * Represents less than 10% Long-lived assets and operating income outside the U.S. are not material; therefore disclosures have been limited to revenue. Foreign Currency Translation The Company’s consolidated financial statements are prepared in U.S. dollars (USD). Its foreign subsidiaries use their local currency as their functional currency and maintain their records in the local currency. Accordingly, the assets and liabilities of these subsidiaries are translated into USD using the current exchange rates in effect at the balance sheet date and equity accounts are translated into USD using historical rates. Revenues and expenses are translated using the monthly average exchange rates during the period when the transaction occurs. The resulting foreign currency translation adjustments from this process are recorded in accumulated other comprehensive income (loss) in the consolidated balance sheets. Unrealized foreign exchange gains and losses from the remeasurement of assets and liabilities denominated in currencies other than the functional currency of the reporting entity are recorded in other income (expense), net. The Company recorded net unrealized foreign currency transaction gains of $0.8 million during the year ended December 31, 2017, losses of $1.6 million during the year ended December 31, 2016 and gains of $0.6 million during the year ended December 31, 2015. Additionally, realized gains and losses resulting from transactions denominated in currencies other than the local currency are recorded in other income (expense), net. The Company recorded realized foreign currency transaction gains of $0.5 million during the year ended December 31, 2017, gains of $0.7 million during the year ended December 31, 2016 and losses of $2.2 million during the year ended December 31, 2015. As the Company’s international operations grow, the effect of fluctuations in currency rates will become greater, and the Company will continue to reassess its approach to managing this risk. In addition, currency fluctuations or a weakening U.S. dollar can increase the costs of the Company’s international expansion. To date, the Company has not entered into any foreign currency hedging contracts. Based on its current international structure, the Company does not plan on engaging in hedging activities in the near future. Use of Estimates The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Significant accounting estimates and management judgments reflected in the consolidated financial statements include items such as allowances for doubtful accounts; warranty obligations; stock-based compensation; depreciation and amortization lives; inventory valuation; valuation of investments and accounting for income taxes. Estimates are based on historical experience, where applicable, and other assumptions believed to be reasonable by management. Actual results may differ from those estimates under different assumptions or conditions. Concentration of Credit Risk and Other Risks and Uncertainties Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents and investments. The majority of the Company’s cash is held by one financial institution in the United States in excess of federally insured limits. The Company maintained investments in money market funds that were not federally insured during the years ended December 31, 2017 and 2016, and held cash in foreign banks of approximately $4.5 million and $3.3 million at December 31, 2017 and 2016, respectively, that was not federally insured. The Company has not experienced any losses on its deposits of cash and cash equivalents. The Company’s convertible note hedge transactions, entered into in connection with the 2021 Notes, subject the Company to credit risk such that the counterparties may be unable to fulfill the terms of the transactions. The associated risk is mitigated by limiting the counterparties to major financial institutions. Through December 31, 2014, all of the Company’s revenue had been derived from sales of its products in international markets, principally Australia and Europe. In May 2015, the Company launched sales in the United States upon receiving FDA approval to market and sell its products in the United States. In the international markets in which the Company participates, the Company uses both a direct sales force and distributors to sell its products, while in the United States the Company utilizes a direct sales force. The Company performs ongoing credit evaluations of some of its direct customers and distributors, does not require collateral, and maintains allowances for potential credit losses on customer accounts when deemed necessary. There were no customers that accounted for 10% or more of the Company’s revenue for each of the years ended December 31, 2017, 2016 and 2015. Additionally, there were no customers that accounted for 10% or more of the Company’s accounts receivable balance as of December 31, 2017 and 2016. The Company is subject to risks common to medical device companies including, but not limited to, new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, product liability, uncertainty of market acceptance of products and the need to obtain additional financing. The Company is dependent on third party manufacturers and suppliers, in some cases sole- or single-source suppliers. There can be no assurance that the Company’s products or services will continue to be accepted in the marketplace, nor can there be any assurance that any future products or services can be developed or manufactured at an acceptable cost and with appropriate performance characteristics, or that such products or services will be successfully marketed, if at all. The Company expects to incur operating losses in the near term and may need to obtain additional financing. There can be no assurance that such financing will be available or will be at terms acceptable by the Company. Fair Value of Financial Instruments Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, short term investments, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents include money market funds in the amount of $30.3 million and $35.5 million as of December 31, 2017 and 2016, respectively. At December 31, 2017 and 2016, the Company’s cash equivalents were held in institutions in the United States and include deposits in a money market fund which were unrestricted as to withdrawal or use. Restricted Cash Restricted cash as of December 31, 2017 and 2016 includes certificates of deposit of $0.6 million representing collateral for the Company’s Redwood City, CA building lease pursuant to an agreement dated March 5, 2015 and $0.2 million collateralizing payment of charges related to the Company’s credit cards. Investment Securities The Company classifies its investment securities as available-for-sale. The Company classifies these investment securities as short-term or long-term based on the nature of the investment, its maturity date and its availability for use in current operations. Those investments with original maturities greater than three months at the date of purchase and remaining maturities of less than 12 months are considered short-term investments. Those investments with remaining maturities greater than 12 months are also classified as short-term investments as management considers them to be available for current operations if needed. The Company’s investment securities are recorded at fair value based on the fair value hierarchy. Money market funds and treasury bonds are classified within Level 1 of the fair value hierarchy and the commercial paper and corporate notes are classified within Level 2 of the fair value hierarchy. Unrealized gains and losses, deemed temporary in nature, are reported as a separate component of accumulated other comprehensive income (loss). A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Premiums (discounts) are amortized (accreted) over the life of the related security as an adjustment to yield using the straight-line interest method. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. Inventories Inventories are stated at the lower of cost to purchase or manufacture the inventory or the net realizable value of such inventory. Cost is determined using the standard cost method which approximates the first-in, first-out basis. Net realizable value is determined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. The Company regularly reviews inventory quantities in consideration of actual loss experiences, projected future demand, and remaining shelf life to record a provision for excess and obsolete inventory when appropriate. The Company’s policy is to write down inventory that has become obsolete, inventory that has a cost basis in excess of its expected lower of cost or net realizable value, and inventory in excess of expected requirements. The estimate of excess quantities is judgmental and primarily dependent on the Company’s estimates of future demand for a particular product. If the estimate of future demand is inaccurate based on actual sales, the Company may increase the write down for excess inventory for that component and record a charge to inventory impairment in the accompanying consolidated statements of operations and comprehensive loss. The Company periodically evaluates the carrying value of inventory on hand for potential excess amount over demand using the same lower of cost or net realizable value approach as that has been used to value the inventory. The Company also periodically evaluates inventory quantities in consideration of actual loss experience. As a result of these evaluations, for the years ended December 31, 2017, 2016 and 2015, the Company recognized total write downs of $4.0 million, $4.1 million and $2.8 million for its inventories. The Company’s estimation of the future demand for a particular component of the Company’s products may vary and may result in changes in estimates in any particular period. Shipping and Handling Costs Shipping and handling costs are expensed as incurred and are included in cost of revenue. Revenue Recognition The Company recognizes revenue when all of the following criteria are met: • persuasive evidence of an arrangement exists; • the sales price is fixed or determinable; • collection of the relevant receivable is reasonably assured at the time of sale; and • delivery has occurred or services have been rendered. For a majority of sales, where the Company’s sales representative delivers its product at the point of implantation at hospitals or medical facilities, the Company recognizes revenue upon completion of the procedure and receipt of the purchase order, which represents satisfaction of the required revenue recognition criteria. For the remaining sales, which are sent from the Company’s distribution centers directly to hospitals and medical facilities, as well as distributor sales where product is ordered in advance of an implantation procedure and a valid purchase order has been received, the Company recognizes revenue at the time of shipment of the product, which represents the point in time when the customer has taken ownership and assumed the risk of loss and the required revenue recognition criteria are satisfied. The Company’s customers are obligated to pay within specified terms regardless of when or if they ever sell or use the products. The Company does not offer rights of return or price protection and it has no post-delivery obligations. The Company periodically provides incentive offers to customers. Product revenue is recorded net of such incentive offers. Allowance for Doubtful Accounts The Company makes estimates of the collectability of accounts receivable. In doing so, the Company analyzes historical bad debt trends, customer credit worthiness, current economic trends and changes in customer payment patterns when evaluating the adequacy of the allowance for doubtful accounts. Warranty Obligations The Company provides a limited one- to five-year warranty and warrants that its products will operate substantially in conformity with product specifications. The Company records an estimate for the provision for warranty claims in cost of revenue when the related revenues are recognized. This estimate is based on historical and anticipated rates of warranty claims, the cost per claim and the number of units sold. The Company regularly assesses the adequacy of its recorded warranty obligations and adjusts the amounts as necessary. Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation of property and equipment, other than leasehold improvements, is computed using the straight-line method over the assets’ estimated useful lives of three to five years. Leasehold improvements are amortized on a straight-line basis over the shorter of the estimated useful life of the asset or the life of the lease. Upon retirement or sale, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs are charged to operations as incurred. Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group might not be recoverable. When such an event occurs, management determines whether there has been impairment by comparing the anticipated undiscounted future net cash flows to the related asset group’s carrying value. If an asset is considered impaired, the asset is written down to fair value, which is determined based either on discounted cash flows or appraised value, depending on the nature of the asset. There were no impairment charges, or changes in estimated useful lives, recorded through December 31, 2017. Income Taxes The Company records income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company’s consolidated financial statements or income tax returns. In estimating future tax consequences, expected future events other than enactments or changes in the tax law or rates are considered. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized. The Company operates in various tax jurisdictions and is subject to audit by various tax authorities. To date, taxes paid have been predominantly due to income taxes in foreign and state jurisdictions in which we conduct business. The Company provides for tax contingencies whenever it is deemed probable that a tax asset has been impaired or a tax liability has been incurred for events such as tax claims or changes in tax laws. Tax contingencies are based upon their technical merits, relative tax law, and the specific facts and circumstances as of each reporting period. Changes in facts and circumstances could result in material changes to the amounts recorded for such tax contingencies. The Company records uncertain tax positions on the basis of a two-step process whereby (1) a determination is made as to whether it is more likely than not that the tax positions will be sustained based on the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold the Company recognizes the largest amount of tax benefit that is greater than 50% likely to be realized upon ultimate settlement with the related tax authority. The Company’s policy is to recognize interest and penalties related to income taxes as a component of income tax expense. No interest or penalties related to income taxes have been recognized in the statements of operations and comprehensive loss in 2017, 2016 and 2015. On December 22, 2017, the 2017 Tax Cuts and Jobs Act (the 2017 Tax Act) was enacted into law. The 2017 Tax Act contains several key tax law changes, including a reduction of the corporate income tax rate to 21% effective January 1, 2018, and a one-time mandatory transition tax on accumulated foreign earnings, among others. In accordance with Accounting Standards Codification (ASC) 740, Income Taxes Other Comprehensive Income (Loss) Other comprehensive income (loss) represents all changes in stockholders’ equity except those resulting from distributions to stockholders. The Company’s unrealized gains on short-term available-for-sale investment securities and foreign currency translation adjustments represent the components of other comprehensive income (loss) that are excluded from the reported net loss and are presented in the consolidated statements of operations and comprehensive loss. Research and Development Research and development expenses, including new product development, regulatory compliance, and clinical research, are charged to operations as incurred in the consolidated statements of operations and comprehensive loss. Such costs include personnel-related costs, including stock-based compensation, supplies, services, depreciation, allocated facilities and information services, clinical trial and related clinical manufacturing expenses, fees paid to investigative sites, and other indirect costs. Stock-Based Compensation The Company accounts for stock-based compensation arrangements with employees in accordance with Accounting Standards Codification (ASC) 718, Compensation—Stock Compensation. In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-09, Stock Compensation (Topic 718): Improvements to Employee Shared-Based Payment Accounting The Company’s determination of the fair value of stock options on the date of grant utilizes the Black-Scholes option-pricing model, and is impacted by its common stock price as well as changes in assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, the expected term that options will remain outstanding, the expected common stock price volatility over the term of the option awards, risk-free interest rates and expected dividends. The fair value of stock options is recognized over the period during which an optionee is required to provide services in exchange for the option award, known as the requisite service period (usually the vesting period), on a straight-line basis. Stock-based compensation expense recognized at fair value includes the impact of estimated forfeitures. The Company estimates future forfeitures at the date of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company estimates the fair value of the rights to purchase shares by employees under the Employee Stock Purchase Plan using the Black-Scholes option pricing formula. The Employee Stock Purchase Plan provides for consecutive six-month offering periods and the Company uses its own historical volatility data in the valuation. Equity instruments issued to non-employees are recorded at their fair value on the measurement date and are subject to periodic adjustments as the underlying equity instruments vest. The fair value of options granted to consultants is expensed when vested. The non-employee stock-based compensation expense was not material for all periods presented. The Company accounts for stock-based compensation for the restricted stock units at their fair value, based on the closing market price of the Company’s common stock on the grant date. These costs are recognized on a straight-line basis over the requisite service period, which is generally the vesting term of four years. The Company also issues stock options and restricted stock units with vesting based upon completion of performance goals. The fair value for these performance-based awards is recognized over the period during which the goals are to be achieved. Stock-based compensation expense recognized at fair value includes the impact of estimated probability that the goals would be achieved, which is assessed prior to the requisite service period for the specific goals. Upon adoption of ASU 2016-09 as described above, excess tax benefits or deficiencies from share-based award activity are reflected in the consolidated statements of operations as a component of the provision for income taxes, whereas they were previously recognized as additional paid-in capital. Net Loss per Share of Common Stock Basic net loss per common share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, restricted stock units and common stock options are considered to be potentially dilutive securities. Because the Company has reported a net loss in all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. Recent Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), Revenue Recognition In the fourth quarter of fiscal 2017, the Company finalized its assessment of the new revenue standard, including completing its contract reviews and evaluation of design changes to business processes and controls. Based on its assessment, the Company notes that its revenue arrangements consist of a single performance obligation and the transfer of promised goods which allows the Company to recognize revenue at a point in time. However, assuming all other revenue recognition criteria have been met, under the new revenue standard, the Company will recognize revenue earlier for arrangements where certain documents required for revenue recognition under the current standard are considered administrative and incidental. The Company will adopt the new revenue standard as of January 1, 2018, using the modified retrospective approach applied to those contracts which were not completed as of that date. Upon adoption, the Company will recognize the cumulative effect of adopting the new revenue standard as an adjustment to the opening balance of the Company’s accumulated deficit. The Company does not expect this adjustment to have a material impact on its consolidated financial statements. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, The Company will adopt ASU 2016-01 in the first quarter of 2018 and does not expect the impact on its consolidated financial statements to be material. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) . The update The Company is evaluating the effect that this new standard will have on its Financial Statements and related disclosures. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other than Inventory asset. This ASU does not apply to intra-entity transfers of inventory, where t he income tax consequences from the sale of inventory from one member of a consolidated entity to another will continue to be deferred until the inventory is sold to a third party. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, a consensus of the FASB Emerging Issues Task Force In February 2017, the FASB issued ASU No. 2017-05, Other Income – Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets. In March 2017, the FASB issued ASU No. 2017-08, Receivables – Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. In May 2017, the FASB issued ASU No. 2017-09, Compensation – Stock Compensation (Topic 718): Scope of Modification Accounting. |
Fair Value Measurements
Fair Value Measurements | 12 Months Ended |
Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | |
Fair Value Measurements | 3. Fair Value Measurements Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability 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 fair value hierarchy defines a three-level valuation hierarchy for disclosure of fair value measurements as follows: • Level 1 — Observable inputs, such as quoted prices in active markets for identical assets or liabilities. • Level 2 — Observable inputs other than Level 1 prices, 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. Cash Equivalents and Short Term Investments The Company’s cash equivalents are comprised of investments in money market funds that are classified as Level 1 of the fair value hierarchy. To value its money market funds, the Company values the funds at $1 stable net asset value, which is the quoted price in active markets for identical assets that the Company has the ability to access. The Company’s short-term investments are comprised of commercial paper and corporate notes. All short-term investments have been classified within Level 1 or Level 2 of the fair value hierarchy because of the sufficient observable inputs for revaluation. The Company’s Level 2 investments are valued using third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of any broker/dealer quotes on the same or similar investments, issuer credit spreads, benchmark investments, prepayment/default projections based on historical data and other observable inputs. The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis, by level, within the fair value hierarchy (in thousands): Balance as of December 31, 2017 Level 1 Level 2 Level 3 Total Assets: Money market funds (i) $ 30,278 $ — $ — $ 30,278 Commercial paper (ii) — 61,086 — 61,086 Corporate notes (ii) — 165,381 — 165,381 Total assets $ 30,278 $ 226,467 $ — $ 256,745 Balance as of December 31, 2016 Level 1 Level 2 Level 3 Total Assets: Money market funds (i) $ 35,510 $ — $ — $ 35,510 Commercial paper (ii) — 160,582 — 160,582 Corporate notes (ii) — 74,369 — 74,369 Total assets $ 35,510 $ 234,951 $ — $ 270,461 (i) Included in cash and cash equivalents on the consolidated balance sheets. (ii) Included in short-term investments on the consolidated balance sheets Convertible Senior Notes As of December 31, 2017, the fair value of the 1.75% convertible senior notes due 2021 was $180.3 million. The fair value was determined on the basis of market prices observable for similar instruments and is considered Level 2 in the fair value hierarchy. |
Balance Sheet Components
Balance Sheet Components | 12 Months Ended |
Dec. 31, 2017 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Balance Sheet Components | 4. Balance Sheet Components Investments The fair value of the Company’s cash equivalents and short-term investments approximates their respective carrying amounts due to their short-term maturity. The following is a summary of the gross unrealized gains and unrealized losses on the Company’s investment securities (in thousands): December 31, 2017 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Investment Securities Commercial paper $ 61,167 $ — $ (81 ) $ 61,086 Corporate notes 165,712 1 (332 ) 165,381 Total securities $ 226,879 $ 1 $ (413 ) $ 226,467 December 31, 2016 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Investment Securities Commercial paper $ 160,729 $ 6 $ (153 ) $ 160,582 Corporate notes 74,430 3 (64 ) 74,369 Total securities $ 235,159 $ 9 $ (217 ) $ 234,951 Realized gains or losses from the sale of investments and other-than-temporary impairments, if any, on available-for-sale securities are reported in other income (expense), net as incurred. The cost of securities sold was determined based on the specific identification method. The amount of realized gains and realized losses on investments for the periods presented have not been material. The amortized costs and estimated fair values of the Company’s available-for-sale securities by contractual maturities as of December 31, 2017 were as follows (in thousands): Amortized Cost Fair Value Amounts maturing within one year $ 204,739 $ 204,385 Amounts after one year through five years 22,140 22,082 Total investment securities $ 226,879 $ 226,467 Inventories (in thousands) December 31, 2017 2016 Raw materials $ 51,602 $ 44,862 Finished goods 46,517 40,359 Total inventories $ 98,119 $ 85,221 Property and Equipment, Net (in thousands) December 31, 2017 2016 Laboratory equipment $ 2,416 $ 1,567 Computer equipment and software 5,076 2,388 Furniture and fixtures 2,241 2,051 Leasehold improvements 1,221 1,214 Construction in process 2,734 2,274 Total 13,688 9,494 Less: Accumulated depreciation and amortization (4,869 ) (2,362 ) Property and equipment, net $ 8,819 $ 7,132 Depreciation and amortization expense for the years ended December 31, 2017, 2016 and 2015 was $2.5 million, $1.7 million and $0.6 million, respectively. Accrued Liabilities (in thousands) December 31, 2017 2016 Accrued payroll and related expenses $ 26,108 $ 17,732 Accrued professional fees 4,734 1,067 Accrued taxes 2,827 2,110 Accrued clinical and research expenses 1,279 1,545 Accrued interest 243 243 Accrued warranty 708 645 Accrued other 3,491 2,686 Total accrued liabilities $ 39,390 $ 26,028 |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2017 | |
Commitments And Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | 5. Commitments and Contingencies Operating Leases In March 2015, the Company entered into a lease agreement for approximately 50,740 square feet of office space located in Redwood City, California for a period beginning in June 2015 through May 2022 with initial annual payments of approximately $2.0 million, increasing to $2.4 million annually during the final year of the lease term. In December 2016, the Company entered into an amendment for an additional approximately 49,980 square feet of office space adjacent to the premises under the original lease (the Expansion Premises), with initial annual payments of $1.2 million, increasing to $2.9 million in the final year of the amended lease term. The lease for the Expansion Premises commences on the earlier of (i) the date the Company commences business operations in the Expansion Premises, or (ii) the date upon which the Landlord substantially completes certain improvements to, and permitting for, the Expansion Premises (the Commencement Date). The Commencement Date is expected to occur in the first half of 2018. The Company entered into a non-cancellable operating lease effective May 1, 2010 for facilities in Menlo Park, California as amended in 2012 to extend the period of the lease until May 31, 2015. In March 2015, the Company extended the lease through September 30, 2015, at which time the lease terminated. In August 2014, the Company entered into a new facility lease for warehouse space beginning on August 21, 2014 through May 31, 2015, under which it was obligated to pay approximately $100,000 in lease payments over the term of the lease. In March 2015, the Company extended the warehouse lease through February 2017 under which it was obligated to pay approximately $0.3 million in lease payments over the remaining term of the lease. In February 2017, the Company entered into a separate non-cancellable facility lease for warehouse space beginning March 1, 2017 through February 28, 2022, under which the Company is obligated to pay approximately $0.4 million in lease payments over the term of the lease. Rent expense for the years ended December 31, 2017, 2016 and 2015 was $2.5 million, $2.4 million and $1.9 million, respectively. Excluding the terms under the amendment for the Expansion Premises, which is subject to certain cancellation clauses, future minimum lease payments under operating leases as of December 31, 2017 are as follows (in thousands): Leases Year ending December 31, 2018 $ 2,288 2019 2,356 2020 2,409 2021 2,484 2022 1,227 Total $ 10,764 Warranty Obligations The Company warrants that its products will operate substantially in conformity with product specifications and provides a limited one- to five-year warranty. Activities related to warranty obligations were as follows (in thousands): December 31, 2017 2016 Beginning Balance $ 645 $ 394 Provision for warranty 1,468 902 Utilization (1,405 ) (651 ) Ending Balance $ 708 $ 645 Supply Agreements The Company has entered into supply agreements with certain of the Company’s suppliers that required certain minimum annual purchase agreements. As of December 31, 2017, the Company had minimum annual purchase commitments $6.6 million due in 2018, $6.4 million due in 2019 and $6.2 million due in 2020. The Company also entered into a service agreement for which it is committed to pay $3.6 million over the term of the service agreement. License Agreements In March 2006, the Company entered into an amended and restated license agreement with the Mayo Foundation for Medical Education and Research (Mayo) and Venturi Group LLC (VGL), which provides the Company access to the certain know how and licensed patents owned by Mayo and VGL for treatment of central, autonomic and peripheral nervous system disorders, including pain, using devices to modulate nerve signaling. The licenses granted are exclusive and the Company has the right to sub-license. The agreement will terminate upon the last to expire patent application, unless terminated earlier. The agreement can be terminated any time after three years from March 2006 by Mayo or VGL. Per terms of the license, the Company is required to pay royalties based on the greater of earned royalty or minimum royalty. The earned royalty will be based on a percentage of net sales of licensed products either by the Company or the sub-licensee. The minimum royalty payment will be based on royalty periods as defined in the agreement. In March 2011, the Company entered into a Phase II License Agreement with Mayo which provides the Company access to the certain know how and licensed patents owned by Mayo. The licenses granted are exclusive and the Company has the right to sub-license. The agreement will terminate upon the last to expire patent application, unless terminated earlier. Per terms of the license, the Company is required to: • Pay a retainer fee of $40,000 per annum starting March 2011 and ending February 2013; • Pay royalties based on the greater of earned royalty or minimum royalty. The earned royalty is based on a percentage of net sales of licensed products either by the Company or the sub-licensee. The minimum annual royalty payment is $200,000. Royalties paid during the years ended December 31, 2017, 2016 and 2015 were $2.5 million, $1.9 million and $0.6 million, respectively. In November 2014, the Company issued Mayo 20,833 shares of common stock owed in connection with the IPO pursuant to the terms of the license, and recorded noncash research and development expense of $0.5 million for the fair value of the shares on the date of issuance. In July 2017, the Company entered into a license agreement for which it is committed to pay $0.5 million over the remaining term of this license agreement, which ends in 2022. Contingencies From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. There have been no contingent liabilities requiring accrual at December 31, 2017 and 2016. Indemnification The Company enters into standard indemnification arrangements in the ordinary course of business. Pursuant to these arrangements, the Company indemnifies, holds harmless, and agrees to reimburse the indemnified parties for losses suffered or incurred by the indemnified party, including, among other circumstances, in connection with any trade secret, copyright, patent or other intellectual property infringement claim by any third-party with respect to the Company’s technology. The term of these indemnification agreements is generally perpetual. The maximum potential amount of future payments the Company could be required to make under these agreements is not determinable because it involves claims that may be made against the Company in the future, but have not yet been made. The Company has entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers, other than liabilities arising from willful misconduct of the individual. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is unlimited; however, the Company has director and officer insurance coverage that reduces the Company’s exposure and enables the Company to recover a portion of any future amounts paid. The Company believes the estimated fair value of these indemnification agreements in excess of applicable insurance coverage is minimal. The Company has not incurred costs to defend lawsuits or settle claims related to these indemnification agreements. No liability associated with such indemnifications has been recorded to date. Legal Matters On November 28, 2016, the Company filed a lawsuit for patent infringement against Boston Scientific Corporation and Boston Scientific Neuromodulation Corporation (collectively, Boston Scientific). The lawsuit, filed in the United States District Court for the Northern District of California, asserts that Boston Scientific is infringing the Company’s patents covering inventions relating to the Senza system and HF10 therapy. The lawsuit seeks preliminary and permanent injunctive relief against further infringement as well as damages and attorney’s fees. On December 9, 2016, Boston Scientific filed a patent infringement lawsuit alleging the Company’s manufacture, use and sale of the Senza system infringes certain of Boston Scientific’s patents covering SCS technology related to stimulation leads, rechargeable batteries and telemetry. The lawsuit, filed in the United States District Court for the District of Delaware, seeks unspecified damages and attorney’s fees, as well as preliminary and permanent injunctive relief against further infringement. As of December 31, 2017, . The Company is and may from time to time continue to be involved in various legal proceedings of a character normally incident to the ordinary course of its business, including several pending European patent oppositions at the European Patent Office (EPO) initiated by the Company’s competitors Medtronic and Boston Scientific, which the Company does not deem to be material to its business and consolidated financial statements at this stage. |
Long-term Debt
Long-term Debt | 12 Months Ended |
Dec. 31, 2017 | |
Debt Disclosure [Abstract] | |
Long-term Debt | 6. Long-term Debt 1.75% Convertible Senior Notes and Convertible Note Hedge and Warrant Transactions In June 2016, the Company issued $150.0 million aggregate principal amount of 1.75% convertible senior notes due 2021 in a registered underwritten public offering and an additional $22.5 million aggregate principal amount of such notes pursuant to the exercise in full of the over-allotment options of the underwriters (the 2021 Notes). The interest rates are fixed at 1.75% per annum and are payable semi-annually in arrears on June 1 and December 1 of each year, commencing on December 1, 2016. The total net proceeds from the debt offering, after deducting initial purchase discounts and debt issuance costs, were approximately $166.2 million. Each $1,000 principal amount of the 2021 Notes will initially be convertible into 10.3770 shares of the Company’s common stock, which is equivalent to an initial conversion price of approximately $96.37 per share, subject to adjustment upon the occurrence of specified events. The 2021 Notes will be convertible at the option of the holders at any time prior to the close of business on the business day immediately preceding December 1, 2020, only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on September 30, 2016 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any ten consecutive trading day period (the measurement period) in which the trading price (as defined in the indenture to the 2021 Notes) per $1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; or (3) upon the occurrence of specified corporate events. On or after December 1, 2020 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 2021 Notes at any time, regardless of the foregoing circumstances. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at the Company’s election. If the Company undergoes a fundamental change prior to the maturity date, holders of the notes may require the Company to repurchase for cash all or any portion of their notes at a repurchase price equal to 100% of the principal amount of the notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. In addition, if specific corporate events occur prior to the applicable maturity date, the Company will increase the conversion rate for a holder who elects to convert their notes in connection with such a corporate event in certain circumstances. It is the Company’s current intent and policy to settle conversions through combination settlement with a specified dollar amount per $1,000 principal amount of notes of $1,000. During the three months ended December 31, 2017, the conditions allowing holders of the 2021 Notes to convert have not been met. The 2021 Notes are therefore not convertible during the three months ended March 31, 2018 and are classified as long-term debt. Should the sale price condition be met in a future quarter, the 2021 Notes will be convertible at the holders’ option during the immediately following quarter. As of December 31, 2017, the if-converted value of the 2021 Notes did not exceed the principal value of those notes. In accounting for the issuance of the convertible senior notes, the Company separated the 2021 Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated convertible feature. The carrying amount of the equity component representing the conversion option was $32.9 million and was determined by deducting the fair value of the liability component from the par value of the 2021 Notes. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount (debt discount) is amortized to interest expense over the term of the 2021 Notes expense at an effective interest rate of 6.29% over the contractual terms of the notes. In accounting for the debt issuance costs of $6.2 million related to the 2021 Notes, the Company allocated the total amount incurred to the liability and equity components of the 2021 Notes based on their relative values. Issuance costs attributable to the liability component were $5.0 million and will be amortized to interest expense using the effective interest method over the contractual terms of the 2021 Notes. Issuance costs attributable to the equity component were netted with the equity component in stockholders’ equity. The net carrying amount of the liability component of the 2021 Notes was as follows (in thousands): December 31, 2017 2016 Principal $ 172,500 $ 172,500 Unamortized discount (23,737 ) (29,783 ) Unamortized issuance cost (3,744 ) (4,577 ) Net carrying amount $ 145,019 $ 138,140 The net carrying amount of the equity component of the 2021 Notes was as follows (in thousands): December 31, 2017 2016 Debt discount related to value of conversion option $ 32,945 $ 32,945 Debt issuance cost (1,179 ) (1,179 ) Net carrying amount $ 31,766 $ 31,766 The following table sets forth the interest expense recognized related to the 2021 Notes (in thousands): Year Ended December 31, 2017 2016 Contractual interest expense $ 3,019 $ 1,652 Amortization of debt discount 6,046 3,162 Amortization of debt issuance costs 833 416 Total interest expense related to the 2021 Notes $ 9,898 $ 5,230 In connection with the offering of the 2021 Notes, the Company entered into convertible note hedge transactions with certain bank counterparties in which the Company has the option to purchase initially (subject to adjustment for certain specified events) a total of approximately 1.8 million shares of the Company’s common stock at a price of approximately $96.37 per share. The total cost of the convertible note hedge transactions was $45.1 million. In addition, the Company sold warrants to certain bank counterparties whereby the holders of the warrants have the option to purchase initially (subject to adjustment for certain specified events) a total of approximately 1.8 million shares of the Company’s common stock at a price of $127.28 per share. The Company received $33.1 million in cash proceeds from the sale of these warrants. Taken together, the purchase of the convertible note hedges and the sale of warrants are intended to offset any actual dilution from the conversion of these notes and to effectively increase the overall conversion price from $96.37 to $127.28 per share. As these transactions meet certain accounting criteria, the convertible note hedges and warrants are recorded in stockholders’ equity and are not accounted for as derivatives. The net cost of $12.0 million incurred in connection with the convertible note hedge and warrant transactions was recorded as a reduction to additional paid-in capital on the consolidated balance sheet. Capital Royalty Term Loan On October 24, 2014, the Company entered into a credit facility (the “credit facility”) with Capital Royalty Partners and certain of its affiliates (the “lenders”) under which, subject to certain conditions, the Company could enter into three term loan agreements totaling $50.0 million with the lenders on or before September 30, 2015. In June 2016, the Company paid the outstanding principal and repayment fees totaling $21.0 million to the lenders, and the credit facility terminated and is now no longer in effect. The difference between the total payment to the lenders and the net carrying amount of the obligation recorded on the balance sheet was recorded as a loss on extinguishment of debt. |
Convertible Preferred Stock
Convertible Preferred Stock | 12 Months Ended |
Dec. 31, 2017 | |
Equity [Abstract] | |
Convertible Preferred Stock | 7. Convertible Preferred Stock Prior to its initial public offering, the Company had outstanding 15,208,048 shares of convertible preferred stock. Each share of preferred stock was convertible to one share of common stock. Upon the closing of the Company’s initial public offering on November 11, 2014, all shares of outstanding redeemable convertible preferred stock were automatically converted to 15,208,048 shares of the Company’s common stock. |
Stock-Based Compensation
Stock-Based Compensation | 12 Months Ended |
Dec. 31, 2017 | |
Equity [Abstract] | |
Stock-Based Compensation | 8. Stock-Based Compensation Common stock reserved for future issuance as of December 31, 2017 was as follows: December 31, 2017 Outstanding stock options and restricted stock units 3,280,812 Reserved for grants of future stock options and restricted stock units 2,466,246 Reserved for employee stock purchase plan 836,635 Total common stock reserved for future issuance 6,583,693 Stock Plans The Company’s Board of Directors (Board) and stockholders previously approved the 2007 Stock Option Plan (the 2007 Plan). In October 2014, the Board adopted the 2014 Equity Incentive Award Plan (the 2014 Plan and, together with the 2007 Plan, the Stock Plans). As of the effective date of the 2014 Plan, the Company suspended the 2007 Plan and no additional awards may be granted under the 2007 Plan. Any shares of common stock covered by awards granted under the 2007 Plan that terminate after the effective date of the 2014 Plan by expiration, forfeiture, cancellation or other means without the issuance of such shares, will be added to the 2014 Plan reserve. Under the 2014 Plan, 1,854,166 shares of common stock were initially reserved for issuance, plus the number of shares remaining available for future awards under the 2007 Plan, as of the pricing of the IPO. The number of shares initially reserved for issuance under the 2014 Plan is subject to increase by (i) the number of shares represented by awards outstanding under the 2007 Plan that are forfeited or lapse unexercised and which following the pricing date are not issued under the 2007 Plan, and (ii) an annual increase on January 1 of each year. Under the 2014 Plan, the Company may grant awards such as incentive stock options, nonstatutory stock options, restricted stock units and stock appreciation rights. Incentive stock options (ISO) may be granted only to Company employees (including directors who are also employees). Nonqualified stock options (NSO) may be granted to Company employees, directors and consultants. Stock Options Options under the 2014 Plan may be granted for periods of up to ten years and at prices no less than 100% of the estimated fair market value of the shares on the date of grant as determined by the Board, provided, however, that the exercise price of an ISO or an NSO granted to a 10% stockholder shall not be less than 110% of the estimated fair market value of the shares on the date of grant. Upon the exercise of options, the Company issues new common stock from its authorized shares. The vesting provisions of individual options vary but are generally over four years, with the exception of performance based stock options. Pursuant to the 2014 Plan, the Company granted performance based stock options to the Company’s CEO in March 2016. This performance based stock option award is subject to the CEO’s continued service to the Company through each applicable vesting date. If a performance metric is not met within the time limits specified in the award agreements, the shares subject to vesting under the vesting tranche for that performance metric will be cancelled. A summary of shares available for grant under the Stock Plans is as follows: Shares Available for Grant Balance at December 31, 2014 1,695,416 Additional shares reserved 994,619 Options and restricted stock granted (975,688 ) Options and restricted stock cancelled 142,362 Balance at December 31, 2015 1,856,709 Additional shares reserved 1,125,742 Options and restricted stock granted (856,043 ) Options and restricted stock cancelled 75,831 Balance at December 31, 2016 2,202,239 Additional shares reserved 1,155,474 Shares forfeited for tax 13,094 Options and restricted stock granted (1,002,063 ) Options and restricted stock cancelled 97,502 Balance at December 31, 2017 2,466,246 A summary of stock option activity under the Stock Plans is as follows: Options Outstanding Weighted Average Number of Weighted Average Remaining Aggregate Options Exercise Price Contractual Term Intrinsic Value (in years) (in thousands) Outstanding at December 31, 2014 2,973,732 $ 5.77 7.9 $ 97,832 Options granted 970,238 $ 50.16 Options exercised (751,610 ) $ 3.87 $ 36,603 Options cancelled (142,072 ) $ 19.08 Outstanding at December 31, 2015 3,050,288 $ 19.74 7.8 $ 145,721 Options granted 498,564 $ 66.74 Options exercised (667,494 ) $ 10.19 $ 46,529 Options cancelled (60,131 ) $ 40.89 Outstanding at December 31, 2016 2,821,227 $ 29.85 7.4 $ 123,425 Options granted 503,690 $ 74.71 Options exercised (707,410 ) $ 10.59 $ 50,971 Options cancelled (57,535 ) $ 46.83 Outstanding at December 31, 2017 2,559,972 $ 43.62 7.3 $ 71,120 Options exercisable as of December 31, 2017 1,413,016 $ 28.23 6.4 $ 58,832 Options vested, exercisable or expected to vest as of December 31, 2017 2,488,146 $ 42.90 7.3 $ 70,702 The aggregate intrinsic value of options exercised is the difference between the estimated fair market value of the Company’s common stock at the date of exercise and the exercise price for in-the-money options. The aggregate intrinsic value of outstanding options is the difference between the closing price as of the date outstanding and the exercise price of the underlying stock options. The weighted-average grant-date fair value of options granted during the years ended December 31, 2017, 2016 and 2015 was $32.35, $32.11 and $25.06 per share, respectively. The total fair value of options vested during the years ended December 31, 2017, 2016 and 2015 was approximately $13.3 million, $10.7 million and $5.2 million, respectively, based on the grant date fair value. The options outstanding and vested under the Stock Plans by exercise price, at December 31, 2017, were as follows: Options Outstanding Options Vested Weighted Average Remaining Number Contractual Term Weighted Average Number Weighted Average Exercise Price Outstanding (in years) Exercise Price Exercisable Exercise Price $0.96 — $1.92 41,048 2.32 $ 1.50 41,048 $ 1.50 $3.60 574,734 5.00 $ 3.60 565,497 $ 3.60 $10.08 — $45.07 524,579 6.95 $ 27.74 352,099 $ 26.88 $45.81 — $63.23 717,583 7.82 $ 56.91 331,152 $ 56.83 $63.39 — $97.52 702,028 9.36 $ 77.12 123,220 $ 77.22 $0.96 — $97.52 2,559,972 7.34 $ 43.62 1,413,016 $ 28.23 Restricted Stock Units In 2015, the Company began granting restricted stock units (RSUs) under the 2014 Plan. Holders of RSUs do not have stockholder rights. Upon the release of RSUs, the Company issues new common stock from its authorized shares. RSUs generally vest four years from the date of grant. Pursuant to the 2014 Plan, the Company granted performance based RSUs to the CEO in March 2016. The performance based RSUs are subject to the CEO’s continued service to the Company through each applicable vesting date. If a performance metric is not met within the time limits specified in the RSU agreement, the shares subject to vesting under the vesting tranche for that performance metric will be cancelled. A summary of RSUs activity under the Stock Plans was as follows: Number of Weighted Average Aggregate Restricted Grant Date Intrinsic Value Stock Units Fair Value (in thousands) Outstanding at December 31, 2014 — $ — $ — Restricted stock granted 5,450 $ 56.47 Restricted stock cancelled (290 ) $ 63.23 Outstanding at December 31, 2015 5,160 $ 56.09 $ 348 Restricted stock granted 357,479 $ 70.31 Restricted stock released (1,384 ) $ 56.65 $ 115 Restricted stock cancelled (15,700 ) $ 65.15 Outstanding at December 31, 2016 345,555 $ 70.39 $ 25,108 Restricted stock granted 498,373 $ 82.60 Restricted stock released (83,121 ) $ 69.90 $ 1,175 Restricted stock cancelled (39,967 ) $ 81.57 Outstanding at December 31, 2017 720,840 $ 78.26 $ 49,767 Restricted stock expected to vest as of December 31, 2017 659,105 $ 45,505 The aggregate intrinsic value of RSUs released is calculated using the fair market value of the Company’s common stock at the date of release. The aggregate intrinsic value of outstanding RSUs is calculated based on the closing price of the Company’s common stock as of the date outstanding. 2014 Employee Stock Purchase Plan In October 2014, the Board adopted the 2014 Employee Stock Purchase Plan (the ESPP). A total of 196,666 shares of common stock were initially available for future issuance under the 2014 Employee Stock Purchase Plan, subject to an annual increase on January 1 of each year. The ESPP provides eligible employees with an opportunity to purchase shares of the Company’s common stock through payroll deductions of up to 15% of their eligible compensation, subject to plan limitations. Under the ESPP, the purchase price of the Company stock is equal to 85% of the lower of its fair market value at the start and end of a six-month purchase period. A summary of ESPP activity was as follows: December 31, 2017 2016 2015 Additional shares reserved 288,868 281,435 248,654 Shares issued 73,262 72,568 33,158 Shares available for future issuance 836,635 621,029 412,162 Employee contributions for shares issued (in thousands) $ 4,697 $ 3,499 $ 1,430 Early Exercises Stock options previously granted under the 2007 Plan allowed the Board of Directors to grant awards to provide employee option holders the right to elect to exercise unvested options in exchange for restricted common stock. Unvested shares, which amounted to 0 at December 31, 2017, 1,836 at December 31, 2016 and 14,863 at December 31, 2015, were subject to a repurchase right held by the Company at the original issue price in the event the optionees’ employment was terminated either voluntarily or involuntarily. For exercises of employee options, this right lapses according to the vesting schedule designated on the associated option grant. The repurchase terms are considered to be a forfeiture provision. The shares purchased by the employees pursuant to the early exercise of stock options are not deemed to be issued or outstanding for accounting purposes until those shares vest, though they are legally issued and outstanding. In addition, cash received from employees for exercise of unvested options is treated as a refundable deposit shown as a liability on the consolidated balance sheets. As of December 31, 2017 and 2016, cash received related to unvested shares totaled $0 and $7,000, respectively. Amounts recorded are transferred into common stock and additional paid-in-capital as the shares vest. Employee Stock-Based Compensation The Company estimated the fair value of stock options granted to employees and shares purchased by employees under the ESPP using the Black-Scholes option valuation model. The fair value is amortized on a straight-line basis over the requisite service period of the awards, with the exception of performance based stock options whose fair value is recorded as expenses when performance metrics are achieved. The following assumptions were used in estimating the fair value: Years Ended December 31, 2017 2016 2015 Stock Options: Expected term (in years) 5.5 5.3 — 6.1 5.3 — 6.1 Expected volatility 44% — 46% 47% — 49% 46% — 59% Risk-free interest rate 1.8% — 2.2% 1.3% — 1.9% 1.4% — 1.8% Dividend Yield 0% 0% 0% ESPP: Expected term (in years) 0.5 0.5 0.5 Expected volatility 36% — 37% 46% — 53% 42% — 64% Risk-free interest rate 1.0% — 1.4% 0.4% — 0.6% 0.1% — 0.3% Dividend Yield 0% 0% 0% Expected Term . The expected term of stock-based awards represents the weighted-average period that the stock-based awards are expected to remain outstanding. The Company has historically opted to use the “simplified method” for estimating the expected term of the awards, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the awards. Starting in late 2016, the Company started to utilize its own historical data for the calculation of expected term. Expected Volatility . The Company has historically determined the share price volatility for stock-based awards based on an analysis of the historical volatilities of a peer group of publicly traded medical device companies. Starting in late 2016, the Company has started to incorporate its own stock trading volatility with those of its peer group for the calculation of volatility. In evaluating similarity, the Company considered factors such as industry, stage of life cycle and size. Risk-Free Interest Rate. The risk-free interest rate is based on the U.S. Treasury yield in effect at the time of the grant for zero-coupon U.S. Treasury notes with remaining terms similar to the expected term of the stock-based awards. Dividend Rate. The expected dividend was assumed to be zero as the Company has never paid dividends and has no current plans to do so. Expected Forfeiture Rate. The Company is required to estimate forfeitures at the time of grant, and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option forfeitures and record stock-based compensation expense only for those awards that are expected to vest. To the extent actual forfeitures differ from the estimates, the difference will be recorded as a cumulative adjustment in the period that the estimates are revised. The Company accounts for RSUs at their fair value, based on the closing market price of the Company’s common stock on the grant date. The fair value is amortized on a straight-line basis over the requisite service period of the awards, with the exception of performance based awards whose fair value is recorded as an expense when performance metrics are achieved. A summary of pre-tax stock-based compensation expense by line items in the consolidated statements of operations was as follows (in thousands): Years Ended December 31, 2017 2016 2015 Cost of revenue $ 1,878 $ 1,094 $ 621 Research and development 4,601 3,182 1,401 Sales, general and administrative 19,664 11,484 5,303 Total stock-based compensation expense $ 26,143 $ 15,760 $ 7,325 The effect of recording pre-tax stock-based compensation expense recognized were as follows (in thousands): Years Ended December 31, 2017 2016 2015 Stock options $ 13,412 $ 10,832 $ 6,679 Restricted stock units 11,197 3,548 9 Employee stock purchase plan 1,534 1,380 637 Total stock-based compensation expense $ 26,143 $ 15,760 $ 7,325 As of December 31, 2017, total stock-based compensation expense not yet recognized, net of estimated forfeitures, were as follows: Unrecognized Weighted-Average Compensation Amortization Period (in thousands) (in years) Stock options $ 28,244 2.5 Restricted stock units 43,435 3.1 Employee stock purchase plan 824 0.4 |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | |
Income Taxes | 9. Income Taxes The components of the Company’s loss before income taxes were as follows: Years Ended December 31, 2017 2016 2015 (in thousands) Domestic $ (39,370 ) $ (34,258 ) $ (68,919 ) Foreign 4,120 4,103 2,654 Total loss before income taxes $ (35,250 ) $ (30,155 ) $ (66,265 ) The components of the provision for income taxes are as follows (in thousands): Years Ended December 31, 2017 2016 2015 Current: Federal $ — $ — $ — State 170 181 34 Foreign 1,238 1,442 1,132 Total current 1,408 1,623 1,166 Deferred: Federal — — — State — — — Foreign — — — Total deferred — — — Total provision for income taxes $ 1,408 $ 1,623 $ 1,166 Income tax expense differs from the amount computed by applying the statutory federal income tax rate as follows: Years Ended December 31, 2017 2016 2015 Tax at statutory federal rate 34.0 % 34.0 % 34.0 % State tax, net of federal benefit (0.4 )% (0.4 )% 0.0 % Other (4.4 )% (3.7 )% (3.5 )% Foreign rate differential 0.5 % (0.2 )% (0.5 )% Tax credits 4.5 % 3.2 % 1.6 % Excess tax benefits related to stock-based compensation 21.5 % — % — % Effect of Tax Cuts and Jobs Act of 2017 (121.1 )% — % — % Change in valuation allowance 61.4 % (38.4 )% (33.4 )% Total (4.0 )% (5.5 )% (1.8 )% The tax effects of temporary differences and carryforwards that give rise to significant portions of deferred tax assets are as follows: December 31, 2017 2016 (in thousands) Net operating loss carryforwards $ 60,999 $ 60,610 Tax credits 10,198 7,655 Depreciation 133 26 Stock-based compensation 6,983 5,207 Accruals and reserves 7,280 7,559 Other 2,525 4,671 Deferred tax assets 88,118 85,728 Other — — Deferred tax liabilities — — Valuation allowance (88,118 ) (85,728 ) Net deferred tax assets $ — $ — The 2017 Tax Act reduces the U.S. statutory corporate tax rate to 21% for the Company’s tax years beginning in 2018, which resulted in the re-measurement of the Company’s federal deferred tax assets as of December 31, 2017 from 34% to the new 21% tax rate. The Company has established a full valuation allowance against its deferred tax assets due to the uncertainty surrounding realization of these assets. Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by $2.4 million, $18.7 million and $23.4 million for the years ended December 31, 2017, 2016 and 2015, respectively. The Company adopted the guidance under ASU 2016-09, Improvements to Employee Share-Based Payment Accounting As of December 31, 2017, the Company had research and development credit carryforwards of approximately $7.7 million and $5.5 million for federal and California state income tax purposes, respectively. The federal credit carryforward begins expiring in 2026, and the state credits carry forward indefinitely. Under Section 382 of the Internal Revenue Code of 1986, as amended, the Company’s ability to utilize NOLs or other tax attributes such as research tax credits, in any taxable year may be limited if the Company experiences, or has experienced, a Section 382 “ownership change.” A Section 382 “ownership change” generally occurs if one or more stockholders or groups of stockholders, who own at least 5% of the Company’s stock, increase their ownership by a greater than 50 percentage point change (by value) over a rolling three-year period. Similar rules may apply under state tax laws. As a result of the Company’s June 2015 underwritten public offering, the Company experienced a Section 382 “ownership change.” The Company currently estimates that this “ownership change” will not inhibit its ability to utilize its NOLs. However, the Company may, in the future, experience one or more additional Section 382 “ownership changes” as a result of subsequent changes in its stock ownership, some of which changes are outside the Company’s control. If so, the Company may not be able to utilize a material portion of its NOLs and tax credits, even if the Company achieves profitability. The Company had unrecognized tax benefits (UTBs) of approximately $4.2 million as of December 31, 2017. The deferred tax assets associated with these UTBs are fully offset by a valuation allowance. The following table summarizes the activity related to UTBs (in thousands): Balance at December 31, 2014 $ 1,962 Increases related to current year tax provisions 813 Increases related to prior year tax provisions 1,069 Balance at December 31, 2015 3,844 Increases related to current year tax provisions 1,059 Decreases related to prior year tax provisions (1,519 ) Balance at December 31, 2016 3,384 Increases related to current year tax provisions 790 Increases related to prior year tax provisions 193 Decreases related to prior year tax provisions (134 ) Balance at December 31, 2017 $ 4,233 All of these UTBs, if recognized, would affect the effective tax rate before consideration of the valuation allowance. In accordance with ASC 740, Income Taxes The Company files U.S. federal and state income tax and foreign income tax returns with varying statues of limitations. The Company’s tax years from inception in 2006 will remain open to examination due to the carryover of the unused NOLs and tax credits. The Company does not have any tax audits or other proceedings pending. The Company does not expect any material changes to the estimated amount of liability associated with its uncertain tax positions within the next twelve months. |
Net Loss Per Share
Net Loss Per Share | 12 Months Ended |
Dec. 31, 2017 | |
Earnings Per Share [Abstract] | |
Net Loss Per Share | 10. Net Loss Per Share The following table summarizes the computation of basic and diluted net loss per share (in thousands, except share and per share data): Years Ended December 31, 2017 2016 2015 Net loss $ (36,658 ) $ (31,778 ) $ (67,431 ) Weighted average shares outstanding 29,424,360 28,492,091 26,603,512 Less: weighted average shares subject to repurchase (306 ) (7,088 ) (21,622 ) Weighted average shares used to compute basic and diluted net loss per share 29,424,054 28,485,003 26,581,890 Net loss per share, basic and diluted $ (1.25 ) $ (1.12 ) $ (2.54 ) Basic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period, determined using the treasury-stock method, if inclusion of these is dilutive. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. The following potentially dilutive securities outstanding at the end of the periods presented have been excluded from the computation of diluted shares outstanding: December 31, 2017 2016 2015 Unreleased restricted stock 720,840 345,555 5,160 Options to purchase common stock 2,559,972 2,821,227 3,050,288 Convertible senior notes 1,790,033 1,790,033 — Warrants related to the issuance of convertible senior notes 1,790,033 1,790,033 — Total 6,860,878 6,746,848 3,055,448 Additionally, since the Company expects to settle the principal amount of its outstanding convertible senior notes in cash, the Company uses the treasury stock method for calculating any potential dilutive effect of the conversion spread on diluted net income per share, if applicable. The conversion spread will have a dilutive impact on diluted net income per share of common stock when the average market price of the Company’s common stock for a given period exceeds the conversion price of $96.37 per share for the 2021 Notes, which has not occurred as of December 31, 2017. |
Employee Benefit Plan
Employee Benefit Plan | 12 Months Ended |
Dec. 31, 2017 | |
Postemployment Benefits [Abstract] | |
Employee Benefit Plan | 11. Employee Benefit Plan. In 2007, the Company adopted a 401(K) plan for its employees whereby eligible employees may contribute up to the maximum amount permitted by the Internal Revenue Code of 1986, as amended. In June 2016, the Company adopted a policy to match a portion of employee contributions for all qualified employees participating in the 401(k) plan. For the years ended December 31, 2017 and 2016, the Company recorded expense of $2.2 million and $1.3 million for matching contributions, respectively. |
Selected Quarterly Financial In
Selected Quarterly Financial Information | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Information Disclosure [Abstract] | |
Selected Quarterly Financial Information | 12. Selected Quarterly Financial Information (Unaudited) Three Months Ended December 31, September 30, June 30, March 31, 2017 2017 2017 2017 (in thousands, except per share data) Total revenue $ 97,963 $ 82,256 $ 78,016 $ 68,439 Gross profit $ 69,512 $ 57,940 $ 53,873 $ 46,368 Loss from operations $ (2,172 ) $ (4,418 ) $ (9,938 ) $ (13,051 ) Net loss $ (4,311 ) $ (6,230 ) $ (11,610 ) $ (14,507 ) Net loss per share, basic and diluted $ (0.15 ) $ (0.21 ) $ (0.40 ) $ (0.50 ) Shares used in computing net loss per common share, basic and diluted 29,664,926 29,513,842 29,351,414 29,159,509 Three Months Ended December 31, September 30, June 30, March 31, 2016 2016 2016 2016 (in thousands, except per share data) Total revenue $ 70,531 $ 60,922 $ 55,400 $ 41,651 Gross profit $ 48,839 $ 41,687 $ 36,558 $ 25,987 Loss from operations $ (6,269 ) $ (1,872 ) $ (5,923 ) $ (9,017 ) Net loss $ (9,825 ) $ (3,886 ) $ (8,779 ) $ (9,288 ) Net loss per share, basic and diluted $ (0.34 ) $ (0.14 ) $ (0.31 ) $ (0.33 ) Shares used in computing net loss per common share, basic and diluted 28,817,333 28,542,760 23,381,253 28,194,457 |
Summary of Significant Accoun19
Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Basis of Presentation | Basis of Presentation These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the U.S. (U.S. GAAP). The consolidated financial statements include the Company’s accounts and those of its four wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated. |
Segments | Segments The chief operating decision maker for the Company is the Chief Executive Officer. The Chief Executive Officer reviews financial information presented on a consolidated basis, accompanied only by information about revenue by geographic region, for purposes of allocating resources and evaluating financial performance. The Company has one business activity and there are no segment managers who are held accountable for operations, operating results or plans for levels or components below the consolidated unit level, other than revenue. Accordingly, the Company has determined that it has a single reportable and operating segment structure. The Company and its Chief Executive Officer evaluate performance based primarily on revenue in the geographic locations in which the Company operates. Until 2015, the Company had derived most of its revenue from sales to customers in Australia and Europe. In May 2015, the U.S. Food and Drug Administration (FDA) approved the Company’s premarket approval (PMA) application to market Senza in the United States and the Company launched sales in the United States in 2015. Revenue by geography is based on the billing address of the customer. The following table sets forth revenue by geographic area for countries with revenue accounting for 10% of more of the total revenue during the periods presented: Years Ended December 31, 2017 2016 2015 United States 81 % 76 % 35 % Australia * * 20 % United Kingdom * * 12 % Germany * * 13 % * Represents less than 10% Long-lived assets and operating income outside the U.S. are not material; therefore disclosures have been limited to revenue. |
Foreign Currency Translation | Foreign Currency Translation The Company’s consolidated financial statements are prepared in U.S. dollars (USD). Its foreign subsidiaries use their local currency as their functional currency and maintain their records in the local currency. Accordingly, the assets and liabilities of these subsidiaries are translated into USD using the current exchange rates in effect at the balance sheet date and equity accounts are translated into USD using historical rates. Revenues and expenses are translated using the monthly average exchange rates during the period when the transaction occurs. The resulting foreign currency translation adjustments from this process are recorded in accumulated other comprehensive income (loss) in the consolidated balance sheets. Unrealized foreign exchange gains and losses from the remeasurement of assets and liabilities denominated in currencies other than the functional currency of the reporting entity are recorded in other income (expense), net. The Company recorded net unrealized foreign currency transaction gains of $0.8 million during the year ended December 31, 2017, losses of $1.6 million during the year ended December 31, 2016 and gains of $0.6 million during the year ended December 31, 2015. Additionally, realized gains and losses resulting from transactions denominated in currencies other than the local currency are recorded in other income (expense), net. The Company recorded realized foreign currency transaction gains of $0.5 million during the year ended December 31, 2017, gains of $0.7 million during the year ended December 31, 2016 and losses of $2.2 million during the year ended December 31, 2015. As the Company’s international operations grow, the effect of fluctuations in currency rates will become greater, and the Company will continue to reassess its approach to managing this risk. In addition, currency fluctuations or a weakening U.S. dollar can increase the costs of the Company’s international expansion. To date, the Company has not entered into any foreign currency hedging contracts. Based on its current international structure, the Company does not plan on engaging in hedging activities in the near future. |
Use of Estimates | Use of Estimates The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Significant accounting estimates and management judgments reflected in the consolidated financial statements include items such as allowances for doubtful accounts; warranty obligations; stock-based compensation; depreciation and amortization lives; inventory valuation; valuation of investments and accounting for income taxes. Estimates are based on historical experience, where applicable, and other assumptions believed to be reasonable by management. Actual results may differ from those estimates under different assumptions or conditions. |
Concentration of Credit Risk and Other Risks and Uncertainties | Concentration of Credit Risk and Other Risks and Uncertainties Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents and investments. The majority of the Company’s cash is held by one financial institution in the United States in excess of federally insured limits. The Company maintained investments in money market funds that were not federally insured during the years ended December 31, 2017 and 2016, and held cash in foreign banks of approximately $4.5 million and $3.3 million at December 31, 2017 and 2016, respectively, that was not federally insured. The Company has not experienced any losses on its deposits of cash and cash equivalents. The Company’s convertible note hedge transactions, entered into in connection with the 2021 Notes, subject the Company to credit risk such that the counterparties may be unable to fulfill the terms of the transactions. The associated risk is mitigated by limiting the counterparties to major financial institutions. Through December 31, 2014, all of the Company’s revenue had been derived from sales of its products in international markets, principally Australia and Europe. In May 2015, the Company launched sales in the United States upon receiving FDA approval to market and sell its products in the United States. In the international markets in which the Company participates, the Company uses both a direct sales force and distributors to sell its products, while in the United States the Company utilizes a direct sales force. The Company performs ongoing credit evaluations of some of its direct customers and distributors, does not require collateral, and maintains allowances for potential credit losses on customer accounts when deemed necessary. There were no customers that accounted for 10% or more of the Company’s revenue for each of the years ended December 31, 2017, 2016 and 2015. Additionally, there were no customers that accounted for 10% or more of the Company’s accounts receivable balance as of December 31, 2017 and 2016. The Company is subject to risks common to medical device companies including, but not limited to, new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, product liability, uncertainty of market acceptance of products and the need to obtain additional financing. The Company is dependent on third party manufacturers and suppliers, in some cases sole- or single-source suppliers. There can be no assurance that the Company’s products or services will continue to be accepted in the marketplace, nor can there be any assurance that any future products or services can be developed or manufactured at an acceptable cost and with appropriate performance characteristics, or that such products or services will be successfully marketed, if at all. The Company expects to incur operating losses in the near term and may need to obtain additional financing. There can be no assurance that such financing will be available or will be at terms acceptable by the Company. |
Fair Value of Financial Instruments | Fair Value of Financial Instruments Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, short term investments, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities. |
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 at the date of purchase to be cash equivalents. Cash and cash equivalents include money market funds in the amount of $30.3 million and $35.5 million as of December 31, 2017 and 2016, respectively. At December 31, 2017 and 2016, the Company’s cash equivalents were held in institutions in the United States and include deposits in a money market fund which were unrestricted as to withdrawal or use. |
Restricted Cash | Restricted Cash Restricted cash as of December 31, 2017 and 2016 includes certificates of deposit of $0.6 million representing collateral for the Company’s Redwood City, CA building lease pursuant to an agreement dated March 5, 2015 and $0.2 million collateralizing payment of charges related to the Company’s credit cards. |
Investment Securities | Investment Securities The Company classifies its investment securities as available-for-sale. The Company classifies these investment securities as short-term or long-term based on the nature of the investment, its maturity date and its availability for use in current operations. Those investments with original maturities greater than three months at the date of purchase and remaining maturities of less than 12 months are considered short-term investments. Those investments with remaining maturities greater than 12 months are also classified as short-term investments as management considers them to be available for current operations if needed. The Company’s investment securities are recorded at fair value based on the fair value hierarchy. Money market funds and treasury bonds are classified within Level 1 of the fair value hierarchy and the commercial paper and corporate notes are classified within Level 2 of the fair value hierarchy. Unrealized gains and losses, deemed temporary in nature, are reported as a separate component of accumulated other comprehensive income (loss). A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Premiums (discounts) are amortized (accreted) over the life of the related security as an adjustment to yield using the straight-line interest method. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. |
Inventories | Inventories Inventories are stated at the lower of cost to purchase or manufacture the inventory or the net realizable value of such inventory. Cost is determined using the standard cost method which approximates the first-in, first-out basis. Net realizable value is determined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. The Company regularly reviews inventory quantities in consideration of actual loss experiences, projected future demand, and remaining shelf life to record a provision for excess and obsolete inventory when appropriate. The Company’s policy is to write down inventory that has become obsolete, inventory that has a cost basis in excess of its expected lower of cost or net realizable value, and inventory in excess of expected requirements. The estimate of excess quantities is judgmental and primarily dependent on the Company’s estimates of future demand for a particular product. If the estimate of future demand is inaccurate based on actual sales, the Company may increase the write down for excess inventory for that component and record a charge to inventory impairment in the accompanying consolidated statements of operations and comprehensive loss. The Company periodically evaluates the carrying value of inventory on hand for potential excess amount over demand using the same lower of cost or net realizable value approach as that has been used to value the inventory. The Company also periodically evaluates inventory quantities in consideration of actual loss experience. As a result of these evaluations, for the years ended December 31, 2017, 2016 and 2015, the Company recognized total write downs of $4.0 million, $4.1 million and $2.8 million for its inventories. The Company’s estimation of the future demand for a particular component of the Company’s products may vary and may result in changes in estimates in any particular period. |
Shipping and Handling Costs | Shipping and Handling Costs Shipping and handling costs are expensed as incurred and are included in cost of revenue. |
Revenue Recognition | Revenue Recognition The Company recognizes revenue when all of the following criteria are met: • persuasive evidence of an arrangement exists; • the sales price is fixed or determinable; • collection of the relevant receivable is reasonably assured at the time of sale; and • delivery has occurred or services have been rendered. For a majority of sales, where the Company’s sales representative delivers its product at the point of implantation at hospitals or medical facilities, the Company recognizes revenue upon completion of the procedure and receipt of the purchase order, which represents satisfaction of the required revenue recognition criteria. For the remaining sales, which are sent from the Company’s distribution centers directly to hospitals and medical facilities, as well as distributor sales where product is ordered in advance of an implantation procedure and a valid purchase order has been received, the Company recognizes revenue at the time of shipment of the product, which represents the point in time when the customer has taken ownership and assumed the risk of loss and the required revenue recognition criteria are satisfied. The Company’s customers are obligated to pay within specified terms regardless of when or if they ever sell or use the products. The Company does not offer rights of return or price protection and it has no post-delivery obligations. The Company periodically provides incentive offers to customers. Product revenue is recorded net of such incentive offers. |
Allowance for Doubtful Accounts | Allowance for Doubtful Accounts The Company makes estimates of the collectability of accounts receivable. In doing so, the Company analyzes historical bad debt trends, customer credit worthiness, current economic trends and changes in customer payment patterns when evaluating the adequacy of the allowance for doubtful accounts. |
Warranty Obligations | Warranty Obligations The Company provides a limited one- to five-year warranty and warrants that its products will operate substantially in conformity with product specifications. The Company records an estimate for the provision for warranty claims in cost of revenue when the related revenues are recognized. This estimate is based on historical and anticipated rates of warranty claims, the cost per claim and the number of units sold. The Company regularly assesses the adequacy of its recorded warranty obligations and adjusts the amounts as necessary. |
Property and Equipment | Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation of property and equipment, other than leasehold improvements, is computed using the straight-line method over the assets’ estimated useful lives of three to five years. Leasehold improvements are amortized on a straight-line basis over the shorter of the estimated useful life of the asset or the life of the lease. Upon retirement or sale, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs are charged to operations as incurred. |
Impairment of Long-Lived Assets | Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group might not be recoverable. When such an event occurs, management determines whether there has been impairment by comparing the anticipated undiscounted future net cash flows to the related asset group’s carrying value. If an asset is considered impaired, the asset is written down to fair value, which is determined based either on discounted cash flows or appraised value, depending on the nature of the asset. There were no impairment charges, or changes in estimated useful lives, recorded through December 31, 2017. |
Income Taxes | Income Taxes The Company records income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company’s consolidated financial statements or income tax returns. In estimating future tax consequences, expected future events other than enactments or changes in the tax law or rates are considered. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized. The Company operates in various tax jurisdictions and is subject to audit by various tax authorities. To date, taxes paid have been predominantly due to income taxes in foreign and state jurisdictions in which we conduct business. The Company provides for tax contingencies whenever it is deemed probable that a tax asset has been impaired or a tax liability has been incurred for events such as tax claims or changes in tax laws. Tax contingencies are based upon their technical merits, relative tax law, and the specific facts and circumstances as of each reporting period. Changes in facts and circumstances could result in material changes to the amounts recorded for such tax contingencies. The Company records uncertain tax positions on the basis of a two-step process whereby (1) a determination is made as to whether it is more likely than not that the tax positions will be sustained based on the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold the Company recognizes the largest amount of tax benefit that is greater than 50% likely to be realized upon ultimate settlement with the related tax authority. The Company’s policy is to recognize interest and penalties related to income taxes as a component of income tax expense. No interest or penalties related to income taxes have been recognized in the statements of operations and comprehensive loss in 2017, 2016 and 2015. On December 22, 2017, the 2017 Tax Cuts and Jobs Act (the 2017 Tax Act) was enacted into law. The 2017 Tax Act contains several key tax law changes, including a reduction of the corporate income tax rate to 21% effective January 1, 2018, and a one-time mandatory transition tax on accumulated foreign earnings, among others. In accordance with Accounting Standards Codification (ASC) 740, Income Taxes |
Other Comprehensive Income (Loss) | Other Comprehensive Income (Loss) Other comprehensive income (loss) represents all changes in stockholders’ equity except those resulting from distributions to stockholders. The Company’s unrealized gains on short-term available-for-sale investment securities and foreign currency translation adjustments represent the components of other comprehensive income (loss) that are excluded from the reported net loss and are presented in the consolidated statements of operations and comprehensive loss. |
Research and Development | Research and Development Research and development expenses, including new product development, regulatory compliance, and clinical research, are charged to operations as incurred in the consolidated statements of operations and comprehensive loss. Such costs include personnel-related costs, including stock-based compensation, supplies, services, depreciation, allocated facilities and information services, clinical trial and related clinical manufacturing expenses, fees paid to investigative sites, and other indirect costs. |
Stock-Based Compensation | Stock-Based Compensation The Company accounts for stock-based compensation arrangements with employees in accordance with Accounting Standards Codification (ASC) 718, Compensation—Stock Compensation. In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-09, Stock Compensation (Topic 718): Improvements to Employee Shared-Based Payment Accounting The Company’s determination of the fair value of stock options on the date of grant utilizes the Black-Scholes option-pricing model, and is impacted by its common stock price as well as changes in assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, the expected term that options will remain outstanding, the expected common stock price volatility over the term of the option awards, risk-free interest rates and expected dividends. The fair value of stock options is recognized over the period during which an optionee is required to provide services in exchange for the option award, known as the requisite service period (usually the vesting period), on a straight-line basis. Stock-based compensation expense recognized at fair value includes the impact of estimated forfeitures. The Company estimates future forfeitures at the date of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company estimates the fair value of the rights to purchase shares by employees under the Employee Stock Purchase Plan using the Black-Scholes option pricing formula. The Employee Stock Purchase Plan provides for consecutive six-month offering periods and the Company uses its own historical volatility data in the valuation. Equity instruments issued to non-employees are recorded at their fair value on the measurement date and are subject to periodic adjustments as the underlying equity instruments vest. The fair value of options granted to consultants is expensed when vested. The non-employee stock-based compensation expense was not material for all periods presented. The Company accounts for stock-based compensation for the restricted stock units at their fair value, based on the closing market price of the Company’s common stock on the grant date. These costs are recognized on a straight-line basis over the requisite service period, which is generally the vesting term of four years. The Company also issues stock options and restricted stock units with vesting based upon completion of performance goals. The fair value for these performance-based awards is recognized over the period during which the goals are to be achieved. Stock-based compensation expense recognized at fair value includes the impact of estimated probability that the goals would be achieved, which is assessed prior to the requisite service period for the specific goals. Upon adoption of ASU 2016-09 as described above, excess tax benefits or deficiencies from share-based award activity are reflected in the consolidated statements of operations as a component of the provision for income taxes, whereas they were previously recognized as additional paid-in capital. |
Net Loss per Share of Common Stock | Net Loss per Share of Common Stock Basic net loss per common share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, restricted stock units and common stock options are considered to be potentially dilutive securities. Because the Company has reported a net loss in all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. |
Recent Accounting Pronouncements | Recent Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), Revenue Recognition In the fourth quarter of fiscal 2017, the Company finalized its assessment of the new revenue standard, including completing its contract reviews and evaluation of design changes to business processes and controls. Based on its assessment, the Company notes that its revenue arrangements consist of a single performance obligation and the transfer of promised goods which allows the Company to recognize revenue at a point in time. However, assuming all other revenue recognition criteria have been met, under the new revenue standard, the Company will recognize revenue earlier for arrangements where certain documents required for revenue recognition under the current standard are considered administrative and incidental. The Company will adopt the new revenue standard as of January 1, 2018, using the modified retrospective approach applied to those contracts which were not completed as of that date. Upon adoption, the Company will recognize the cumulative effect of adopting the new revenue standard as an adjustment to the opening balance of the Company’s accumulated deficit. The Company does not expect this adjustment to have a material impact on its consolidated financial statements. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, The Company will adopt ASU 2016-01 in the first quarter of 2018 and does not expect the impact on its consolidated financial statements to be material. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) . The update The Company is evaluating the effect that this new standard will have on its Financial Statements and related disclosures. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other than Inventory asset. This ASU does not apply to intra-entity transfers of inventory, where t he income tax consequences from the sale of inventory from one member of a consolidated entity to another will continue to be deferred until the inventory is sold to a third party. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, a consensus of the FASB Emerging Issues Task Force In February 2017, the FASB issued ASU No. 2017-05, Other Income – Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets. In March 2017, the FASB issued ASU No. 2017-08, Receivables – Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. In May 2017, the FASB issued ASU No. 2017-09, Compensation – Stock Compensation (Topic 718): Scope of Modification Accounting. |
Summary of Significant Accoun20
Summary of Significant Accounting Policies (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Schedule of Revenue by Major Customers by Geographic Area | The following table sets forth revenue by geographic area for countries with revenue accounting for 10% of more of the total revenue during the periods presented: Years Ended December 31, 2017 2016 2015 United States 81 % 76 % 35 % Australia * * 20 % United Kingdom * * 12 % Germany * * 13 % * Represents less than 10% |
Fair Value Measurements (Tables
Fair Value Measurements (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | |
Financial Instruments Measured at Fair Value on Recurring Basis | The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis, by level, within the fair value hierarchy (in thousands): Balance as of December 31, 2017 Level 1 Level 2 Level 3 Total Assets: Money market funds (i) $ 30,278 $ — $ — $ 30,278 Commercial paper (ii) — 61,086 — 61,086 Corporate notes (ii) — 165,381 — 165,381 Total assets $ 30,278 $ 226,467 $ — $ 256,745 Balance as of December 31, 2016 Level 1 Level 2 Level 3 Total Assets: Money market funds (i) $ 35,510 $ — $ — $ 35,510 Commercial paper (ii) — 160,582 — 160,582 Corporate notes (ii) — 74,369 — 74,369 Total assets $ 35,510 $ 234,951 $ — $ 270,461 (i) Included in cash and cash equivalents on the consolidated balance sheets. (ii) Included in short-term investments on the consolidated balance sheets |
Balance Sheet Components (Table
Balance Sheet Components (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Summary of Gross Unrealized Gains and Unrealized Losses of Investment Securities Excluding Investments in Money Market Funds | The following is a summary of the gross unrealized gains and unrealized losses on the Company’s investment securities (in thousands): December 31, 2017 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Investment Securities Commercial paper $ 61,167 $ — $ (81 ) $ 61,086 Corporate notes 165,712 1 (332 ) 165,381 Total securities $ 226,879 $ 1 $ (413 ) $ 226,467 December 31, 2016 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value Investment Securities Commercial paper $ 160,729 $ 6 $ (153 ) $ 160,582 Corporate notes 74,430 3 (64 ) 74,369 Total securities $ 235,159 $ 9 $ (217 ) $ 234,951 |
Summary of Amortized Costs and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities | The amortized costs and estimated fair values of the Company’s available-for-sale securities by contractual maturities as of December 31, 2017 were as follows (in thousands): Amortized Cost Fair Value Amounts maturing within one year $ 204,739 $ 204,385 Amounts after one year through five years 22,140 22,082 Total investment securities $ 226,879 $ 226,467 |
Components of Inventories | Inventories (in thousands) December 31, 2017 2016 Raw materials $ 51,602 $ 44,862 Finished goods 46,517 40,359 Total inventories $ 98,119 $ 85,221 |
Schedule of Property and Equipment, Net and Depreciation and Amortization Expense | Property and Equipment, Net (in thousands) December 31, 2017 2016 Laboratory equipment $ 2,416 $ 1,567 Computer equipment and software 5,076 2,388 Furniture and fixtures 2,241 2,051 Leasehold improvements 1,221 1,214 Construction in process 2,734 2,274 Total 13,688 9,494 Less: Accumulated depreciation and amortization (4,869 ) (2,362 ) Property and equipment, net $ 8,819 $ 7,132 |
Summary of Accrued Liabilities | Accrued Liabilities (in thousands) December 31, 2017 2016 Accrued payroll and related expenses $ 26,108 $ 17,732 Accrued professional fees 4,734 1,067 Accrued taxes 2,827 2,110 Accrued clinical and research expenses 1,279 1,545 Accrued interest 243 243 Accrued warranty 708 645 Accrued other 3,491 2,686 Total accrued liabilities $ 39,390 $ 26,028 |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Commitments And Contingencies Disclosure [Abstract] | |
Schedule of Future Minimum Lease Payments under Operating Leases | Excluding the terms under the amendment for the Expansion Premises, which is subject to certain cancellation clauses, future minimum lease payments under operating leases as of December 31, 2017 are as follows (in thousands): Leases Year ending December 31, 2018 $ 2,288 2019 2,356 2020 2,409 2021 2,484 2022 1,227 Total $ 10,764 |
Schedule of Activities Related to Warranty Obligations | Activities related to warranty obligations were as follows (in thousands): December 31, 2017 2016 Beginning Balance $ 645 $ 394 Provision for warranty 1,468 902 Utilization (1,405 ) (651 ) Ending Balance $ 708 $ 645 |
Long-term Debt (Tables)
Long-term Debt (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Debt Instrument [Line Items] | |
Interest Expense Recognized Related to Convertible Notes | The following table sets forth the interest expense recognized related to the 2021 Notes (in thousands): Year Ended December 31, 2017 2016 Contractual interest expense $ 3,019 $ 1,652 Amortization of debt discount 6,046 3,162 Amortization of debt issuance costs 833 416 Total interest expense related to the 2021 Notes $ 9,898 $ 5,230 |
Debt, Liability Component [Member] | |
Debt Instrument [Line Items] | |
Net Carrying Amount of Convertible Debt | The net carrying amount of the liability component of the 2021 Notes was as follows (in thousands): December 31, 2017 2016 Principal $ 172,500 $ 172,500 Unamortized discount (23,737 ) (29,783 ) Unamortized issuance cost (3,744 ) (4,577 ) Net carrying amount $ 145,019 $ 138,140 |
Debt, Equity Component [Member] | |
Debt Instrument [Line Items] | |
Net Carrying Amount of Convertible Debt | The net carrying amount of the equity component of the 2021 Notes was as follows (in thousands): December 31, 2017 2016 Debt discount related to value of conversion option $ 32,945 $ 32,945 Debt issuance cost (1,179 ) (1,179 ) Net carrying amount $ 31,766 $ 31,766 |
Stock-Based Compensation (Table
Stock-Based Compensation (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Equity [Abstract] | |
Summary of Common Stock Reserved for Future Issuance | Common stock reserved for future issuance as of December 31, 2017 was as follows: December 31, 2017 Outstanding stock options and restricted stock units 3,280,812 Reserved for grants of future stock options and restricted stock units 2,466,246 Reserved for employee stock purchase plan 836,635 Total common stock reserved for future issuance 6,583,693 |
Summary of Shares Available for Grant | A summary of shares available for grant under the Stock Plans is as follows: Shares Available for Grant Balance at December 31, 2014 1,695,416 Additional shares reserved 994,619 Options and restricted stock granted (975,688 ) Options and restricted stock cancelled 142,362 Balance at December 31, 2015 1,856,709 Additional shares reserved 1,125,742 Options and restricted stock granted (856,043 ) Options and restricted stock cancelled 75,831 Balance at December 31, 2016 2,202,239 Additional shares reserved 1,155,474 Shares forfeited for tax 13,094 Options and restricted stock granted (1,002,063 ) Options and restricted stock cancelled 97,502 Balance at December 31, 2017 2,466,246 |
Summary of Activity under Stock Plans | A summary of stock option activity under the Stock Plans is as follows: Options Outstanding Weighted Average Number of Weighted Average Remaining Aggregate Options Exercise Price Contractual Term Intrinsic Value (in years) (in thousands) Outstanding at December 31, 2014 2,973,732 $ 5.77 7.9 $ 97,832 Options granted 970,238 $ 50.16 Options exercised (751,610 ) $ 3.87 $ 36,603 Options cancelled (142,072 ) $ 19.08 Outstanding at December 31, 2015 3,050,288 $ 19.74 7.8 $ 145,721 Options granted 498,564 $ 66.74 Options exercised (667,494 ) $ 10.19 $ 46,529 Options cancelled (60,131 ) $ 40.89 Outstanding at December 31, 2016 2,821,227 $ 29.85 7.4 $ 123,425 Options granted 503,690 $ 74.71 Options exercised (707,410 ) $ 10.59 $ 50,971 Options cancelled (57,535 ) $ 46.83 Outstanding at December 31, 2017 2,559,972 $ 43.62 7.3 $ 71,120 Options exercisable as of December 31, 2017 1,413,016 $ 28.23 6.4 $ 58,832 Options vested, exercisable or expected to vest as of December 31, 2017 2,488,146 $ 42.90 7.3 $ 70,702 |
Summary of Options Outstanding and Vested under Stock Plans by Exercise Price | The options outstanding and vested under the Stock Plans by exercise price, at December 31, 2017, were as follows: Options Outstanding Options Vested Weighted Average Remaining Number Contractual Term Weighted Average Number Weighted Average Exercise Price Outstanding (in years) Exercise Price Exercisable Exercise Price $0.96 — $1.92 41,048 2.32 $ 1.50 41,048 $ 1.50 $3.60 574,734 5.00 $ 3.60 565,497 $ 3.60 $10.08 — $45.07 524,579 6.95 $ 27.74 352,099 $ 26.88 $45.81 — $63.23 717,583 7.82 $ 56.91 331,152 $ 56.83 $63.39 — $97.52 702,028 9.36 $ 77.12 123,220 $ 77.22 $0.96 — $97.52 2,559,972 7.34 $ 43.62 1,413,016 $ 28.23 |
Summary of Restricted Stock Units under the Stock Plan | A summary of RSUs activity under the Stock Plans was as follows: Number of Weighted Average Aggregate Restricted Grant Date Intrinsic Value Stock Units Fair Value (in thousands) Outstanding at December 31, 2014 — $ — $ — Restricted stock granted 5,450 $ 56.47 Restricted stock cancelled (290 ) $ 63.23 Outstanding at December 31, 2015 5,160 $ 56.09 $ 348 Restricted stock granted 357,479 $ 70.31 Restricted stock released (1,384 ) $ 56.65 $ 115 Restricted stock cancelled (15,700 ) $ 65.15 Outstanding at December 31, 2016 345,555 $ 70.39 $ 25,108 Restricted stock granted 498,373 $ 82.60 Restricted stock released (83,121 ) $ 69.90 $ 1,175 Restricted stock cancelled (39,967 ) $ 81.57 Outstanding at December 31, 2017 720,840 $ 78.26 $ 49,767 Restricted stock expected to vest as of December 31, 2017 659,105 $ 45,505 |
Schedule of Employee Stock Purchase Plan Activity | A summary of ESPP activity was as follows: December 31, 2017 2016 2015 Additional shares reserved 288,868 281,435 248,654 Shares issued 73,262 72,568 33,158 Shares available for future issuance 836,635 621,029 412,162 Employee contributions for shares issued (in thousands) $ 4,697 $ 3,499 $ 1,430 |
Schedule of Fair Value of Employee Stock Options Using Black-Scholes Option Valuation Model | The following assumptions were used in estimating the fair value: Years Ended December 31, 2017 2016 2015 Stock Options: Expected term (in years) 5.5 5.3 — 6.1 5.3 — 6.1 Expected volatility 44% — 46% 47% — 49% 46% — 59% Risk-free interest rate 1.8% — 2.2% 1.3% — 1.9% 1.4% — 1.8% Dividend Yield 0% 0% 0% ESPP: Expected term (in years) 0.5 0.5 0.5 Expected volatility 36% — 37% 46% — 53% 42% — 64% Risk-free interest rate 1.0% — 1.4% 0.4% — 0.6% 0.1% — 0.3% Dividend Yield 0% 0% 0% |
Summary of Stock-Based Compensation Expense by Line Items in Consolidated Statements of Operations | A summary of pre-tax stock-based compensation expense by line items in the consolidated statements of operations was as follows (in thousands): Years Ended December 31, 2017 2016 2015 Cost of revenue $ 1,878 $ 1,094 $ 621 Research and development 4,601 3,182 1,401 Sales, general and administrative 19,664 11,484 5,303 Total stock-based compensation expense $ 26,143 $ 15,760 $ 7,325 |
Summary of Stock-Based Compensation Expense | The effect of recording pre-tax stock-based compensation expense recognized were as follows (in thousands): Years Ended December 31, 2017 2016 2015 Stock options $ 13,412 $ 10,832 $ 6,679 Restricted stock units 11,197 3,548 9 Employee stock purchase plan 1,534 1,380 637 Total stock-based compensation expense $ 26,143 $ 15,760 $ 7,325 |
Summary of Stock-Based Compensation Expense Not Yet Recognized | As of December 31, 2017, total stock-based compensation expense not yet recognized, net of estimated forfeitures, were as follows: Unrecognized Weighted-Average Compensation Amortization Period (in thousands) (in years) Stock options $ 28,244 2.5 Restricted stock units 43,435 3.1 Employee stock purchase plan 824 0.4 |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | |
Components of Loss before Income Taxes | The components of the Company’s loss before income taxes were as follows: Years Ended December 31, 2017 2016 2015 (in thousands) Domestic $ (39,370 ) $ (34,258 ) $ (68,919 ) Foreign 4,120 4,103 2,654 Total loss before income taxes $ (35,250 ) $ (30,155 ) $ (66,265 ) |
Components of Provision for Income Taxes | The components of the provision for income taxes are as follows (in thousands): Years Ended December 31, 2017 2016 2015 Current: Federal $ — $ — $ — State 170 181 34 Foreign 1,238 1,442 1,132 Total current 1,408 1,623 1,166 Deferred: Federal — — — State — — — Foreign — — — Total deferred — — — Total provision for income taxes $ 1,408 $ 1,623 $ 1,166 |
Income Tax Expense by Applying Statutory Federal Income Tax Rate | Income tax expense differs from the amount computed by applying the statutory federal income tax rate as follows: Years Ended December 31, 2017 2016 2015 Tax at statutory federal rate 34.0 % 34.0 % 34.0 % State tax, net of federal benefit (0.4 )% (0.4 )% 0.0 % Other (4.4 )% (3.7 )% (3.5 )% Foreign rate differential 0.5 % (0.2 )% (0.5 )% Tax credits 4.5 % 3.2 % 1.6 % Excess tax benefits related to stock-based compensation 21.5 % — % — % Effect of Tax Cuts and Jobs Act of 2017 (121.1 )% — % — % Change in valuation allowance 61.4 % (38.4 )% (33.4 )% Total (4.0 )% (5.5 )% (1.8 )% |
Tax Effects of Temporary Differences and Carryforwards that Give Rise to Significant Portions of Deferred Tax Assets | The tax effects of temporary differences and carryforwards that give rise to significant portions of deferred tax assets are as follows: December 31, 2017 2016 (in thousands) Net operating loss carryforwards $ 60,999 $ 60,610 Tax credits 10,198 7,655 Depreciation 133 26 Stock-based compensation 6,983 5,207 Accruals and reserves 7,280 7,559 Other 2,525 4,671 Deferred tax assets 88,118 85,728 Other — — Deferred tax liabilities — — Valuation allowance (88,118 ) (85,728 ) Net deferred tax assets $ — $ — |
Summary of Unrecognized Tax Benefits | The following table summarizes the activity related to UTBs (in thousands): Balance at December 31, 2014 $ 1,962 Increases related to current year tax provisions 813 Increases related to prior year tax provisions 1,069 Balance at December 31, 2015 3,844 Increases related to current year tax provisions 1,059 Decreases related to prior year tax provisions (1,519 ) Balance at December 31, 2016 3,384 Increases related to current year tax provisions 790 Increases related to prior year tax provisions 193 Decreases related to prior year tax provisions (134 ) Balance at December 31, 2017 $ 4,233 |
Net Loss Per Share (Tables)
Net Loss Per Share (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Earnings Per Share [Abstract] | |
Computation of Basic and Diluted Net Loss per Share | The following table summarizes the computation of basic and diluted net loss per share (in thousands, except share and per share data): Years Ended December 31, 2017 2016 2015 Net loss $ (36,658 ) $ (31,778 ) $ (67,431 ) Weighted average shares outstanding 29,424,360 28,492,091 26,603,512 Less: weighted average shares subject to repurchase (306 ) (7,088 ) (21,622 ) Weighted average shares used to compute basic and diluted net loss per share 29,424,054 28,485,003 26,581,890 Net loss per share, basic and diluted $ (1.25 ) $ (1.12 ) $ (2.54 ) |
Computation of Potentially Dilutive Securities Outstanding Excluded from Computation of Diluted Shares | The following potentially dilutive securities outstanding at the end of the periods presented have been excluded from the computation of diluted shares outstanding: December 31, 2017 2016 2015 Unreleased restricted stock 720,840 345,555 5,160 Options to purchase common stock 2,559,972 2,821,227 3,050,288 Convertible senior notes 1,790,033 1,790,033 — Warrants related to the issuance of convertible senior notes 1,790,033 1,790,033 — Total 6,860,878 6,746,848 3,055,448 |
Selected Quarterly Financial 28
Selected Quarterly Financial Information (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Information Disclosure [Abstract] | |
Schedule of Selected Quarterly Financial Information | Three Months Ended December 31, September 30, June 30, March 31, 2017 2017 2017 2017 (in thousands, except per share data) Total revenue $ 97,963 $ 82,256 $ 78,016 $ 68,439 Gross profit $ 69,512 $ 57,940 $ 53,873 $ 46,368 Loss from operations $ (2,172 ) $ (4,418 ) $ (9,938 ) $ (13,051 ) Net loss $ (4,311 ) $ (6,230 ) $ (11,610 ) $ (14,507 ) Net loss per share, basic and diluted $ (0.15 ) $ (0.21 ) $ (0.40 ) $ (0.50 ) Shares used in computing net loss per common share, basic and diluted 29,664,926 29,513,842 29,351,414 29,159,509 Three Months Ended December 31, September 30, June 30, March 31, 2016 2016 2016 2016 (in thousands, except per share data) Total revenue $ 70,531 $ 60,922 $ 55,400 $ 41,651 Gross profit $ 48,839 $ 41,687 $ 36,558 $ 25,987 Loss from operations $ (6,269 ) $ (1,872 ) $ (5,923 ) $ (9,017 ) Net loss $ (9,825 ) $ (3,886 ) $ (8,779 ) $ (9,288 ) Net loss per share, basic and diluted $ (0.34 ) $ (0.14 ) $ (0.31 ) $ (0.33 ) Shares used in computing net loss per common share, basic and diluted 28,817,333 28,542,760 23,381,253 28,194,457 |
Formation and Business of the29
Formation and Business of the Company - Additional Information (Detail) - USD ($) $ in Thousands | 1 Months Ended | 3 Months Ended | 12 Months Ended | |||||||||
Jun. 30, 2016 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Formation and Business of the Company [Line Items] | ||||||||||||
Net loss | $ 4,311 | $ 6,230 | $ 11,610 | $ 14,507 | $ 9,825 | $ 3,886 | $ 8,779 | $ 9,288 | $ 36,658 | $ 31,778 | $ 67,431 | |
Cash used in operations | 14,273 | 58,503 | $ 100,430 | |||||||||
Accumulated deficit | $ 257,844 | $ 221,186 | $ 257,844 | $ 221,186 | ||||||||
1.75% Convertible Senior Notes due 2021 [Member] | ||||||||||||
Formation and Business of the Company [Line Items] | ||||||||||||
Debt instrument due year | 2,021 | 2,021 |
Formation and Business of the30
Formation and Business of the Company - Additional Information - Public Offering (Detail) - USD ($) | 1 Months Ended | 12 Months Ended | |||
Jun. 30, 2016 | Jun. 30, 2015 | Nov. 30, 2014 | Dec. 31, 2017 | Dec. 31, 2015 | |
Subsidiary, Sale of Stock [Line Items] | |||||
Common stock, shares issued | 2,470,587 | ||||
Net proceeds from common stock | $ 118,400,000 | $ 131,600,000 | |||
1.75% Convertible Senior Notes due 2021 [Member] | |||||
Subsidiary, Sale of Stock [Line Items] | |||||
Aggregate principal amount of convertible senior notes | $ 150,000,000 | ||||
Debt instrument interest rate | 1.75% | 1.75% | |||
Debt instrument due year | 2,021 | 2,021 | |||
Additional aggregate principal amount of convertible senior notes | $ 22,500,000 | ||||
Debt instrument frequency of payment | semi-annually in arrears on June 1 and December 1 of each year, commencing on December 1, 2016 | ||||
Net proceeds from the debt offering after deducting transaction costs | $ 166,200,000 | ||||
Common Stock [Member] | |||||
Subsidiary, Sale of Stock [Line Items] | |||||
Common stock, shares issued | 2,470,587 | ||||
IPO [Member] | |||||
Subsidiary, Sale of Stock [Line Items] | |||||
Common stock, shares issued | 8,050,000 | ||||
Common stock, shares issued price per share | $ 18 | ||||
IPO [Member] | Common Stock [Member] | |||||
Subsidiary, Sale of Stock [Line Items] | |||||
Shares issued upon conversion of redeemable convertible preferred stock and convertible preferred stock | 15,208,048 | ||||
Over Allotment Option [Member] | |||||
Subsidiary, Sale of Stock [Line Items] | |||||
Common stock, shares issued | 705,882 | 1,050,000 |
Summary of Significant Accoun31
Summary of Significant Accounting Policies - Additional Information (Detail) | 1 Months Ended | 12 Months Ended | |||
Jun. 30, 2016 | Dec. 31, 2018 | Dec. 31, 2017USD ($)SubsidiaryBusinessCustomer | Dec. 31, 2016USD ($)Customer | Dec. 31, 2015USD ($)Customer | |
Summary Of Significant Accounting Policies [Line Items] | |||||
Number of wholly owned subsidiaries | Subsidiary | 4 | ||||
Number of business activities | Business | 1 | ||||
Net unrealized foreign currency transaction gains (losses) | $ 800,000 | $ (1,600,000) | $ 600,000 | ||
Realized foreign currency transaction gains (losses) | 500,000 | 700,000 | (2,200,000) | ||
Cash held in foreign banks | 4,500,000 | 3,300,000 | |||
Money market funds | 30,300,000 | 35,500,000 | |||
Restricted cash | 806,000 | 806,000 | |||
Write down of inventory | $ 3,984,000 | 4,056,000 | 2,767,000 | ||
Standard product warranty, description | Limited one- to five-year warranty | ||||
Impairment charges | $ 0 | ||||
Interest or penalties recognized | $ 0 | $ 0 | $ 0 | ||
U.S. corporate income tax rate | 34.00% | 34.00% | 34.00% | ||
Employee stock purchase plan offering period | 6 months | ||||
RSU's [Member] | |||||
Summary Of Significant Accounting Policies [Line Items] | |||||
Vesting term | 4 years | ||||
Scenario Forecast [Member] | |||||
Summary Of Significant Accounting Policies [Line Items] | |||||
U.S. corporate income tax rate | 21.00% | ||||
Minimum [Member] | |||||
Summary Of Significant Accounting Policies [Line Items] | |||||
Estimated useful life of property and equipment | 3 years | ||||
Maximum [Member] | |||||
Summary Of Significant Accounting Policies [Line Items] | |||||
Estimated useful life of property and equipment | 5 years | ||||
Certificate of Deposit [Member] | |||||
Summary Of Significant Accounting Policies [Line Items] | |||||
Restricted cash | $ 600,000 | $ 600,000 | |||
Collateralizing Payment Charges Related to Credit Cards [Member] | |||||
Summary Of Significant Accounting Policies [Line Items] | |||||
Restricted cash | $ 200,000 | $ 200,000 | |||
Customer Concentration Risk [Member] | Revenue [Member] | |||||
Summary Of Significant Accounting Policies [Line Items] | |||||
Concentration risk, percentage | 10.00% | 10.00% | 10.00% | ||
Number of customers accounted 10% or more concentration risk | Customer | 0 | 0 | 0 | ||
Credit Concentration Risk [Member] | Accounts Receivable [Member] | |||||
Summary Of Significant Accounting Policies [Line Items] | |||||
Concentration risk, percentage | 10.00% | 10.00% | |||
Number of customers accounted 10% or more concentration risk | Customer | 0 | 0 | |||
1.75% Convertible Senior Notes due 2021 [Member] | |||||
Summary Of Significant Accounting Policies [Line Items] | |||||
Debt instrument due year | 2,021 | 2,021 |
Summary of Significant Accoun32
Summary of Significant Accounting Policies - Schedule of Revenue by Major Customers by Geographic Area (Detail) - Revenue [Member] - Geographic Concentration Risk [Member] | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
United States [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 81.00% | 76.00% | 35.00% |
Australia [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 20.00% | ||
United Kingdom [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 12.00% | ||
Germany [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 13.00% |
Summary of Significant Accoun33
Summary of Significant Accounting Policies - Schedule of Revenue by Major Customers by Geographic Area (Parenthetical) (Detail) - Revenue [Member] - Geographic Concentration Risk [Member] | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
United States [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 81.00% | 76.00% | 35.00% |
Australia [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 20.00% | ||
Australia [Member] | Maximum [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 10.00% | 10.00% | |
United Kingdom [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 12.00% | ||
United Kingdom [Member] | Maximum [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 10.00% | 10.00% | |
Germany [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 13.00% | ||
Germany [Member] | Maximum [Member] | |||
Concentration Risk [Line Items] | |||
Revenue | 10.00% | 10.00% |
Fair Value Measurements - Addit
Fair Value Measurements - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions | 1 Months Ended | 12 Months Ended |
Jun. 30, 2016 | Dec. 31, 2017 | |
1.75% Convertible Senior Notes due 2021 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Debt instrument interest rate | 1.75% | 1.75% |
Debt instrument due year | 2,021 | 2,021 |
Fair value of notes | $ 180.3 | |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Net asset value of market funds | $ 1 |
Fair Value Measurements - Finan
Fair Value Measurements - Financial Instruments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total assets | $ 256,745 | $ 270,461 |
Level 1 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total assets | 30,278 | 35,510 |
Level 2 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total assets | 226,467 | 234,951 |
Money Market Funds [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total assets | 30,278 | 35,510 |
Money Market Funds [Member] | Level 1 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total assets | 30,278 | 35,510 |
Commercial Paper [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total assets | 61,086 | 160,582 |
Commercial Paper [Member] | Level 2 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total assets | 61,086 | 160,582 |
Corporate Notes [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total assets | 165,381 | 74,369 |
Corporate Notes [Member] | Level 2 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total assets | $ 165,381 | $ 74,369 |
Balance Sheet Components - Summ
Balance Sheet Components - Summary of Gross Unrealized Gains and Unrealized Losses of Investment Securities in Cash on Hand and Money Market Funds (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Schedule of Available-for-sale Securities [Line Items] | ||
Amortized Cost | $ 226,879 | $ 235,159 |
Gross Unrealized Holding Gains | 1 | 9 |
Gross Unrealized Holding Losses | (413) | (217) |
Aggregate Fair Value | 226,467 | 234,951 |
Commercial Paper [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Amortized Cost | 61,167 | 160,729 |
Gross Unrealized Holding Gains | 6 | |
Gross Unrealized Holding Losses | (81) | (153) |
Aggregate Fair Value | 61,086 | 160,582 |
Corporate Notes [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Amortized Cost | 165,712 | 74,430 |
Gross Unrealized Holding Gains | 1 | 3 |
Gross Unrealized Holding Losses | (332) | (64) |
Aggregate Fair Value | $ 165,381 | $ 74,369 |
Balance Sheet Components - Su37
Balance Sheet Components - Summary of Amortized Costs and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Investments Debt And Equity Securities [Abstract] | ||
Amortized Cost, Amounts maturing within one year | $ 204,739 | |
Amortized Cost, Amounts after one year through five years | 22,140 | |
Amortized Cost | 226,879 | $ 235,159 |
Fair Value, Amounts maturing within one year | 204,385 | |
Fair Value, Amounts after one year through five years | 22,082 | |
Fair Value, Total investment securities | $ 226,467 | $ 234,951 |
Balance Sheet Components - Comp
Balance Sheet Components - Components of Inventories (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Inventory Disclosure [Abstract] | ||
Raw materials | $ 51,602 | $ 44,862 |
Finished goods | 46,517 | 40,359 |
Total inventories | $ 98,119 | $ 85,221 |
Balance Sheet Components - Sche
Balance Sheet Components - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | $ 13,688 | $ 9,494 |
Less: Accumulated depreciation and amortization | (4,869) | (2,362) |
Property and equipment, net | 8,819 | 7,132 |
Laboratory Equipment [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 2,416 | 1,567 |
Computer Equipment and Software [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 5,076 | 2,388 |
Furniture and Fixtures [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 2,241 | 2,051 |
Leasehold Improvements [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 1,221 | 1,214 |
Construction in Process [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | $ 2,734 | $ 2,274 |
Balance Sheet Components - Addi
Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Balance Sheet Components [Abstract] | |||
Depreciation and amortization expense | $ 2,507 | $ 1,717 | $ 614 |
Balance Sheet Components - Su41
Balance Sheet Components - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 |
Payables And Accruals [Abstract] | |||
Accrued payroll and related expenses | $ 26,108 | $ 17,732 | |
Accrued professional fees | 4,734 | 1,067 | |
Accrued taxes | 2,827 | 2,110 | |
Accrued clinical and research expenses | 1,279 | 1,545 | |
Accrued interest | 243 | 243 | |
Accrued warranty | 708 | 645 | $ 394 |
Accrued other | 3,491 | 2,686 | |
Total accrued liabilities | $ 39,390 | $ 26,028 |
Commitments and Contingencies -
Commitments and Contingencies - Additional Information (Detail) | May 31, 2015USD ($) | Jul. 31, 2017USD ($) | Apr. 30, 2017ft² | Feb. 28, 2017USD ($) | Jun. 30, 2015shares | Nov. 30, 2014USD ($)shares | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($)ft² | Dec. 31, 2015USD ($) | Mar. 31, 2015USD ($)ft² |
Other Commitments [Line Items] | ||||||||||
Lease expense, payment due | $ 2,288,000 | |||||||||
Rent expense | $ 2,500,000 | $ 2,400,000 | $ 1,900,000 | |||||||
Standard product warranty, description | Limited one- to five-year warranty | |||||||||
Retainer fees | $ 37,560,000 | 33,729,000 | 21,382,000 | |||||||
Common stock, shares issued | shares | 2,470,587 | |||||||||
Contingent liabilities | 0 | 0 | ||||||||
Indemnification Agreement [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Contingent liabilities | 0 | |||||||||
Patent Infringement [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Contingent liabilities | 0 | |||||||||
Service Agreement [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Service agreement commitment amount | 3,600,000 | |||||||||
Licensing Agreements [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Annual royalty payment | $ 2,500,000 | $ 1,900,000 | $ 600,000 | |||||||
License agreement commitment amount | $ 500,000 | |||||||||
License agreement expiration year | 2,022 | |||||||||
Licensing Agreements [Member] | Mayo And VGL [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
License agreement, terms | The agreement will terminate upon the last to expire patent application, unless terminated earlier. The agreement can be terminated any time after three years from March 2006 by Mayo or VGL. | |||||||||
Licensing Agreements [Member] | Mayo Foundation [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Retainer fees | $ 40,000 | |||||||||
Common stock, shares issued | shares | 20,833 | |||||||||
Noncash research and development expense | $ 500,000 | |||||||||
Licensing Agreements [Member] | Mayo Foundation [Member] | Minimum [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Annual royalty payment | 200,000 | |||||||||
Supply Agreements [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Purchase commitment, amount due in 2018 | 6,600,000 | |||||||||
Purchase commitment, amount due in 2019 | 6,400,000 | |||||||||
Purchase commitment, amount due in 2020 | $ 6,200,000 | |||||||||
Redwood Office Agreement [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Lease agreement, commencement period | 2015-03 | |||||||||
Area of office space | ft² | 50,740 | |||||||||
Lease agreement, effective date | Jun. 30, 2015 | |||||||||
Lease agreement, expiration period | 2022-05 | |||||||||
Lease expense, payment due | $ 2,000,000 | |||||||||
Annual lease expense payable in final year of lease term | $ 2,400,000 | |||||||||
Redwood Office Agreement Additional Expansion Premises [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Area of office space | ft² | 8,171 | 49,980 | ||||||||
Lease agreement, effective date | May 31, 2017 | |||||||||
Lease expense, payment due | $ 1,200,000 | |||||||||
Annual lease expense payable in final year of lease term | $ 2,900,000 | |||||||||
Commencement date description | The lease for the Expansion Premises commences on the earlier of (i) the date the Company commences business operations in the Expansion Premises, or (ii) the date upon which the Landlord substantially completes certain improvements to, and permitting for, the Expansion Premises (the Commencement Date). The Commencement Date is expected to occur in the first half of 2018. | |||||||||
Menlo Park Agreement, Original [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Lease agreement, effective date | May 1, 2010 | |||||||||
Lease agreement, expiration date | May 31, 2015 | |||||||||
Menlo Park Agreement, Extended [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Lease agreement, commencement period | 2015-03 | |||||||||
Lease agreement, expiration date | Sep. 30, 2015 | |||||||||
Lease agreement, lease expense | $ 100,000 | |||||||||
Facility Lease Agreement, Original [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Lease agreement, commencement period | 2014-08 | |||||||||
Lease agreement, effective date | Aug. 21, 2014 | |||||||||
Lease agreement, expiration date | May 31, 2015 | |||||||||
Facility Lease Agreement, Extended [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Lease agreement, commencement period | 2015-03 | |||||||||
Lease agreement, expiration period | 2017-02 | |||||||||
Lease agreement, lease expense | $ 300,000 | |||||||||
Non-cancellable Facility Lease [Member] | ||||||||||
Other Commitments [Line Items] | ||||||||||
Lease agreement, effective date | Mar. 1, 2017 | |||||||||
Lease agreement, expiration date | Feb. 28, 2022 | |||||||||
Lease agreement, lease expense | $ 400,000 |
Commitments and Contingencies43
Commitments and Contingencies - Schedule of Future Minimum Lease Payments under Operating Leases (Detail) $ in Thousands | Dec. 31, 2017USD ($) |
Leases [Abstract] | |
2,018 | $ 2,288 |
2,019 | 2,356 |
2,020 | 2,409 |
2,021 | 2,484 |
2,022 | 1,227 |
Total | $ 10,764 |
Commitments and Contingencies44
Commitments and Contingencies - Schedule of Activities Related to Warranty Obligations (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Commitments And Contingencies Disclosure [Abstract] | ||
Beginning Balance | $ 645 | $ 394 |
Provision for warranty | 1,468 | 902 |
Utilization | (1,405) | (651) |
Ending Balance | $ 708 | $ 645 |
Long-term Debt - Additional Inf
Long-term Debt - Additional Information (Detail) | Oct. 24, 2014USD ($)Term_loan | Jun. 30, 2016USD ($)d$ / sharesshares | Dec. 31, 2017 | Dec. 31, 2016USD ($) |
Debt Instrument [Line Items] | ||||
Proceeds from issuance of warrants | $ 33,120,000 | |||
Repayment of outstanding principal and fees | $ 19,500,000 | |||
Credit Facility [Member] | ||||
Debt Instrument [Line Items] | ||||
Number of term loan agreements | Term_loan | 3 | |||
1.75% Convertible Senior Notes due 2021 [Member] | ||||
Debt Instrument [Line Items] | ||||
Aggregate principal amount of convertible senior notes | $ 150,000,000 | |||
Debt instrument interest rate | 1.75% | 1.75% | ||
Debt instrument due year | 2,021 | 2,021 | ||
Additional aggregate principal amount of convertible senior notes | $ 22,500,000 | |||
Debt instrument frequency of payment | semi-annually in arrears on June 1 and December 1 of each year, commencing on December 1, 2016 | |||
Net proceeds from the debt offering after deducting transaction costs | 166,200,000 | |||
Convertible notes principal amount | $ 1,000 | |||
Convertible notes, shares issued | shares | 10.3770 | |||
Convertible notes, type of equity security issued | common stock | |||
Convertible notes, conversion price | $ / shares | $ 96.37 | |||
Debt instrument convertible, percentage of conversion price | 130.00% | |||
Percentage of repurchase price, which is equal to principal amount of convertible notes | 100.00% | |||
Debt instrument combination settlement | $ 1,000 | |||
Debt conversion, converted instrument amount | $ 32,900,000 | |||
Debt instrument, effective interest rate | 6.29% | |||
Debt issuance costs attributable to the liability and equity component, total amount | $ 6,200,000 | |||
Debt issuance costs attributable to the liability component | $ 5,000,000 | |||
Number of shares purchased under convertible note hedge transactions | shares | 1,800,000 | |||
Purchase price of the shares issued under convertible note hedge transactions | $ / shares | $ 96.37 | |||
Total cost of the convertible note hedge transactions | $ 45,100,000 | |||
Proceeds from issuance of warrants | 33,100,000 | |||
Net cost of reduction to additional paid-in capital | $ 12,000,000 | |||
1.75% Convertible Senior Notes due 2021 [Member] | Warrant [Member] | ||||
Debt Instrument [Line Items] | ||||
Number of shares issued for warrants under convertible note hedge transactions | shares | 1,800,000 | |||
Purchase price of the shares issued under convertible note hedge transactions | $ / shares | $ 127.28 | |||
1.75% Convertible Senior Notes due 2021 [Member] | 130% for Applicable Conversion Price [Member] | ||||
Debt Instrument [Line Items] | ||||
Debt instrument convertible trading days | d | 20 | |||
Debt instrument convertible consecutive trading days | d | 30 | |||
1.75% Convertible Senior Notes due 2021 [Member] | 98% Applicable Conversion Price [Member] | ||||
Debt Instrument [Line Items] | ||||
Debt instrument convertible trading days | d | 5 | |||
Debt instrument convertible consecutive trading days | d | 10 | |||
1.75% Convertible Senior Notes due 2021 [Member] | Maximum [Member] | ||||
Debt Instrument [Line Items] | ||||
Percentage of closing sale price of common stock | 98.00% | |||
1.75% Convertible Senior Notes due 2021 [Member] | Maximum [Member] | Warrant [Member] | ||||
Debt Instrument [Line Items] | ||||
Overall conversion price | $ / shares | $ 127.28 | |||
1.75% Convertible Senior Notes due 2021 [Member] | Minimum [Member] | Warrant [Member] | ||||
Debt Instrument [Line Items] | ||||
Overall conversion price | $ / shares | $ 96.37 | |||
Capital Royalty Term Loan [Member] | Credit Facility [Member] | ||||
Debt Instrument [Line Items] | ||||
Credit facility borrowing capacity | $ 50,000,000 | |||
Credit facility expiration date | Sep. 30, 2015 | |||
Repayment of outstanding principal and fees | $ 21,000,000 |
Long-term Debt - Net Carrying A
Long-term Debt - Net Carrying Amount of Liability Component of Convertible Debt (Detail) - 1.75% Convertible Senior Notes due 2021 [Member] - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 | Jun. 30, 2016 |
Debt Instrument [Line Items] | |||
Unamortized issuance cost | $ (5,000) | ||
Debt, Liability Component [Member] | |||
Debt Instrument [Line Items] | |||
Principal | $ 172,500 | $ 172,500 | |
Unamortized discount | (23,737) | (29,783) | |
Unamortized issuance cost | (3,744) | (4,577) | |
Net carrying amount | $ 145,019 | $ 138,140 |
Long-term Debt - Net Carrying47
Long-term Debt - Net Carrying Amount of Equity Component of Convertible Debt (Detail) - 1.75% Convertible Senior Notes due 2021 [Member] - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 | Jun. 30, 2016 |
Debt Instrument [Line Items] | |||
Net carrying amount | $ 32,900 | ||
Debt, Equity Component [Member] | |||
Debt Instrument [Line Items] | |||
Debt discount related to value of conversion option | $ 32,945 | $ 32,945 | |
Debt issuance cost | (1,179) | (1,179) | |
Net carrying amount | $ 31,766 | $ 31,766 |
Long-term Debt - Interest Expen
Long-term Debt - Interest Expense Recognized Related to Convertible Notes (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Debt Instrument [Line Items] | |||
Amortization of debt issuance costs | $ 6,884 | $ 3,681 | $ 231 |
1.75% Convertible Senior Notes due 2021 [Member] | |||
Debt Instrument [Line Items] | |||
Contractual interest expense | 3,019 | 1,652 | |
Amortization of debt discount | 6,046 | 3,162 | |
Amortization of debt issuance costs | 833 | 416 | |
Total interest expense related to the 2021 Notes | $ 9,898 | $ 5,230 |
Convertible Preferred Stock - A
Convertible Preferred Stock - Additional Information (Detail) - shares | Nov. 11, 2014 | Dec. 31, 2017 | Dec. 31, 2016 | Nov. 10, 2014 |
Class of Stock [Line Items] | ||||
Convertible preferred stock outstanding | 0 | 0 | 15,208,048 | |
IPO [Member] | ||||
Class of Stock [Line Items] | ||||
Convertible preferred stock converted to common stock | 15,208,048 | |||
Common Stock [Member] | ||||
Class of Stock [Line Items] | ||||
Common stock shares issued for each convertible preferred stock | 1 |
Stock-Based Compensation - Summ
Stock-Based Compensation - Summary of Common Stock Reserved for Future Issuance (Detail) | Dec. 31, 2017shares |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Outstanding stock options and restricted stock units | 3,280,812 |
Reserved for grants of future stock options and restricted stock units | 2,466,246 |
Reserved for employee stock purchase plan | 836,635 |
Total common stock reserved for future issuance | 6,583,693 |
Stock-Based Compensation - Addi
Stock-Based Compensation - Additional Information (Detail) - USD ($) | 12 Months Ended | |||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Oct. 31, 2014 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Common stock reserved for future issuance | 6,583,693 | |||
Weighted-average grant-date fair value of options granted | $ 32.35 | $ 32.11 | $ 25.06 | |
Fair value of options vested | $ 13,300,000 | $ 10,700,000 | $ 5,200,000 | |
Employee stock purchase plan offering period | 6 months | |||
Stock options unvested shares | 0 | 1,836 | 14,863 | |
Cash received from unvested shares | $ 0 | $ 7,000 | ||
Employee Stock [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Option purchase price, percentage of fair value | 85.00% | |||
Number of shares available for sale | 196,666 | |||
Maximum employee subscription rate | 15.00% | |||
2007 Plan [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Additional awards authorized under plan | 0 | |||
2014 Plan [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Common stock reserved for future issuance | 1,854,166 | |||
Plan modification description | The number of shares initially reserved for issuance under the 2014 Plan is subject to increase by (i) the number of shares represented by awards outstanding under the 2007 Plan that are forfeited or lapse unexercised and which following the pricing date are not issued under the 2007 Plan, and (ii) an annual increase on January 1 of each year. | |||
2014 Plan [Member] | ISO [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Percentage of shareholder granted option | 10.00% | |||
2014 Plan [Member] | NSO [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Percentage of shareholder granted option | 10.00% | |||
2014 Plan [Member] | Share-based Compensation Award, Tranche One [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Vesting term | 4 years | |||
2014 Plan [Member] | Maximum [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Stock options expiration period | 10 years | |||
Option purchase price, percentage of fair value | 110.00% | |||
2014 Plan [Member] | Minimum [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Option purchase price, percentage of fair value | 100.00% |
Stock-Based Compensation - Su52
Stock-Based Compensation - Summary of Shares Available for Grant (Detail) - shares | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Stock Options [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Shares Available for Grant, Beginning balances | 2,202,239 | 1,856,709 | 1,695,416 |
Shares Available for Grant, Additional shares reserved | 1,155,474 | 1,125,742 | 994,619 |
Shares Available for Grant, Shares forfeited for tax | 13,094 | ||
Shares Available for Grant, Ending balances | 2,466,246 | 2,202,239 | 1,856,709 |
Employee Stock Option and Restricted Stock [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Shares Available for Grant, Options and other than options granted | (1,002,063) | (856,043) | (975,688) |
Shares Available for Grant, Options and other than options forfeited or cancelled | 97,502 | 75,831 | 142,362 |
Stock-Based Compensation - Su53
Stock-Based Compensation - Summary of Activity under Stock Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended | |||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | |
Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Exercise Price And Additional Disclosures [Abstract] | ||||
Number of Options, Outstanding Beginning balances | 2,821,227 | 3,050,288 | 2,973,732 | |
Number of Options, Options granted | 503,690 | 498,564 | 970,238 | |
Number of Options, Options exercised | (707,410) | (667,494) | (751,610) | |
Number of Options, Options cancelled | (57,535) | (60,131) | (142,072) | |
Number of Options, Outstanding Ending balances | 2,559,972 | 2,821,227 | 3,050,288 | 2,973,732 |
Number of Options, Options exercisable | 1,413,016 | |||
Number of Options, Options vested, exercisable or expected to vest | 2,488,146 | |||
Weighted Average Exercise Price, Beginning balances | $ 29.85 | $ 19.74 | $ 5.77 | |
Weighted Average Exercise Price, Options granted | 74.71 | 66.74 | 50.16 | |
Weighted Average Exercise Price, Options exercised | 10.59 | 10.19 | 3.87 | |
Weighted Average Exercise Price, Options cancelled | 46.83 | 40.89 | 19.08 | |
Weighted Average Exercise Price, Ending balances | 43.62 | $ 29.85 | $ 19.74 | $ 5.77 |
Weighted Average Exercise Price, Options exercisable | 28.23 | |||
Weighted Average Exercise Price, Options vested, exercisable or expected to vest | $ 42.90 | |||
Options Outstanding, Weighted-Average Remaining Contractual Term | 7 years 3 months 18 days | 7 years 4 months 24 days | 7 years 9 months 18 days | 7 years 10 months 24 days |
Options exercisable, Weighted-Average Remaining Contractual Term | 6 years 4 months 24 days | |||
Options vested, exercisable or expected to vest, Weighted Average Remaining Contractual Term | 7 years 3 months 18 days | |||
Options Outstanding, Aggregate Intrinsic Value | $ 71,120 | $ 123,425 | $ 145,721 | $ 97,832 |
Options exercised, Aggregate Intrinsic Value | 50,971 | $ 46,529 | $ 36,603 | |
Options exercisable, Aggregate Intrinsic Value | 58,832 | |||
Options vested, exercisable or expected to vest, Aggregate Intrinsic Value | $ 70,702 |
Stock-Based Compensation - Su54
Stock-Based Compensation - Summary of Options Outstanding and Vested Under Stock Plans by Exercise Price (Detail) | 12 Months Ended |
Dec. 31, 2017$ / sharesshares | |
$0.96 - $1.92 [Member] | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] | |
Options Outstanding, Exercise Price Lower Range Limit | $ 0.96 |
Options Outstanding, Exercise Price Upper Range Limit | $ 1.92 |
Number of Options Outstanding | shares | 41,048 |
Options Outstanding, Weighted Average Remaining Contractual Life (in Years) | 2 years 3 months 25 days |
Options Outstanding, Weighted Average Exercise Price | $ 1.50 |
Options Vested, Number Exercisable | shares | 41,048 |
Options Vested, Weighted Average Exercise Price | $ 1.50 |
$3.60 [Member] | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] | |
Options Outstanding, Exercise Price Upper Range Limit | $ 3.60 |
Number of Options Outstanding | shares | 574,734 |
Options Outstanding, Weighted Average Remaining Contractual Life (in Years) | 5 years |
Options Outstanding, Weighted Average Exercise Price | $ 3.60 |
Options Vested, Number Exercisable | shares | 565,497 |
Options Vested, Weighted Average Exercise Price | $ 3.60 |
$10.08 - $45.07 [Member] | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] | |
Options Outstanding, Exercise Price Lower Range Limit | 10.08 |
Options Outstanding, Exercise Price Upper Range Limit | $ 45.07 |
Number of Options Outstanding | shares | 524,579 |
Options Outstanding, Weighted Average Remaining Contractual Life (in Years) | 6 years 11 months 12 days |
Options Outstanding, Weighted Average Exercise Price | $ 27.74 |
Options Vested, Number Exercisable | shares | 352,099 |
Options Vested, Weighted Average Exercise Price | $ 26.88 |
$45.81 - $63.23 [Member] | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] | |
Options Outstanding, Exercise Price Lower Range Limit | 45.81 |
Options Outstanding, Exercise Price Upper Range Limit | $ 63.23 |
Number of Options Outstanding | shares | 717,583 |
Options Outstanding, Weighted Average Remaining Contractual Life (in Years) | 7 years 9 months 25 days |
Options Outstanding, Weighted Average Exercise Price | $ 56.91 |
Options Vested, Number Exercisable | shares | 331,152 |
Options Vested, Weighted Average Exercise Price | $ 56.83 |
$63.39 - $97.52 [Member] | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] | |
Options Outstanding, Exercise Price Lower Range Limit | 63.39 |
Options Outstanding, Exercise Price Upper Range Limit | $ 97.52 |
Number of Options Outstanding | shares | 702,028 |
Options Outstanding, Weighted Average Remaining Contractual Life (in Years) | 9 years 4 months 9 days |
Options Outstanding, Weighted Average Exercise Price | $ 77.12 |
Options Vested, Number Exercisable | shares | 123,220 |
Options Vested, Weighted Average Exercise Price | $ 77.22 |
$0.96 - $97.52 [Member] | |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] | |
Options Outstanding, Exercise Price Lower Range Limit | 0.96 |
Options Outstanding, Exercise Price Upper Range Limit | $ 97.52 |
Number of Options Outstanding | shares | 2,559,972 |
Options Outstanding, Weighted Average Remaining Contractual Life (in Years) | 7 years 4 months 2 days |
Options Outstanding, Weighted Average Exercise Price | $ 43.62 |
Options Vested, Number Exercisable | shares | 1,413,016 |
Options Vested, Weighted Average Exercise Price | $ 28.23 |
Stock-Based Compensation - Su55
Stock-Based Compensation - Summary of Restricted Stock Units Under Stock Plan (Detail) - Restricted Stock Units [Member] - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Number of Restricted Stock Units, Outstanding Beginning Balance | 345,555 | 5,160 | |
Number of Restricted Stock Units, Restricted stock granted | 498,373 | 357,479 | 5,450 |
Number of Restricted Stock Units, Restricted stock released | (83,121) | (1,384) | |
Number of Restricted Stock Units, Restricted stock cancelled | (39,967) | (15,700) | (290) |
Number of Restricted Stock Units, Outstanding Ending Balance | 720,840 | 345,555 | 5,160 |
Number of Restricted Stock Units, Restricted stock expected to vest | 659,105 | ||
Weighted Average Grant Date Fair Value Outstanding, Beginning Balance | $ 70.39 | $ 56.09 | |
Weighted Average Grant Date Fair Value, Granted | 82.60 | 70.31 | $ 56.47 |
Weighted Average Grant Date Fair Value, Released | 69.90 | 56.65 | |
Weighted Average Grant Date Fair Value, Cancelled | 81.57 | 65.15 | 63.23 |
Weighted Average Grant Date Fair Value Outstanding, Ending Balance | $ 78.26 | $ 70.39 | $ 56.09 |
Aggregate Intrinsic Value Outstanding | $ 49,767 | $ 25,108 | $ 348 |
Aggregate Intrinsic Value, Released | 1,175 | $ 115 | |
Aggregate Intrinsic Value, Expected to vest | $ 45,505 |
Stock-Based Compensation - Sche
Stock-Based Compensation - Schedule of Employee Stock Purchase Plan Activity (Detail) - ESPP [Member] - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Additional shares reserved | 288,868 | 281,435 | 248,654 |
Shares issued | 73,262 | 72,568 | 33,158 |
Shares available for future issuance | 836,635 | 621,029 | 412,162 |
Employee contributions for shares issued | $ 4,697 | $ 3,499 | $ 1,430 |
Stock-Based Compensation - Sc57
Stock-Based Compensation - Schedule of Fair Value of Employee Stock Options Using Black-Scholes Option Valuation Model (Detail) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Stock Options [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected volatility, minimum | 44.00% | 47.00% | 46.00% |
Expected volatility, maximum | 46.00% | 49.00% | 59.00% |
Risk-free interest rate, minimum | 1.80% | 1.30% | 1.40% |
Risk-free interest rate, maximum | 2.20% | 1.90% | 1.80% |
Dividend Yield | 0.00% | 0.00% | 0.00% |
Stock Options [Member] | Minimum [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected term (in years) | 5 years 6 months | 5 years 3 months 18 days | 5 years 3 months 18 days |
Stock Options [Member] | Maximum [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected term (in years) | 6 years 1 month 6 days | 6 years 1 month 6 days | |
ESPP [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected term (in years) | 6 months | 6 months | 6 months |
Expected volatility, minimum | 36.00% | 46.00% | 42.00% |
Expected volatility, maximum | 37.00% | 53.00% | 64.00% |
Risk-free interest rate, minimum | 1.00% | 0.40% | 0.10% |
Risk-free interest rate, maximum | 1.40% | 0.60% | 0.30% |
Dividend Yield | 0.00% | 0.00% | 0.00% |
Stock-Based Compensation - Su58
Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Line Items in Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
Stock-based compensation expense | $ 26,143 | $ 15,760 | $ 7,325 |
Cost of Revenue [Member] | |||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
Stock-based compensation expense | 1,878 | 1,094 | 621 |
Research and Development [Member] | |||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
Stock-based compensation expense | 4,601 | 3,182 | 1,401 |
Selling, General and Administrative [Member] | |||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
Stock-based compensation expense | $ 19,664 | $ 11,484 | $ 5,303 |
Stock-Based Compensation - Su59
Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
Stock-based compensation expense | $ 26,143 | $ 15,760 | $ 7,325 |
Stock Options [Member] | |||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
Stock-based compensation expense | 13,412 | 10,832 | 6,679 |
Restricted Stock Units [Member] | |||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
Stock-based compensation expense | 11,197 | 3,548 | 9 |
Employee Stock Purchase Plan [Member] | |||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
Stock-based compensation expense | $ 1,534 | $ 1,380 | $ 637 |
Stock-Based Compensation - Su60
Stock-Based Compensation - Summary of Stock-Based Compensation Expense Not Yet Recognized (Detail) $ in Thousands | 12 Months Ended |
Dec. 31, 2017USD ($) | |
Stock Options [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
Unrecognized Compensation | $ 28,244 |
Weighted-Average Amortization Period (in years) | 2 years 6 months |
Restricted Stock Units [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
Unrecognized Compensation | $ 43,435 |
Weighted-Average Amortization Period (in years) | 3 years 1 month 6 days |
Employee Stock Purchase Plan [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
Unrecognized Compensation | $ 824 |
Weighted-Average Amortization Period (in years) | 4 months 24 days |
Income Taxes - Components of Lo
Income Taxes - Components of Loss before Income Taxes (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax Disclosure [Abstract] | |||
Domestic | $ (39,370) | $ (34,258) | $ (68,919) |
Foreign | 4,120 | 4,103 | 2,654 |
Loss before income taxes | $ (35,250) | $ (30,155) | $ (66,265) |
Income Taxes - Components of Pr
Income Taxes - Components of Provision for Income Taxes (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Current: | |||
Federal | $ 0 | ||
State | $ 170 | $ 181 | 34 |
Foreign | 1,238 | 1,442 | 1,132 |
Total current | 1,408 | 1,623 | 1,166 |
Deferred: | |||
Federal | 0 | ||
State | 0 | ||
Foreign | 0 | ||
Total deferred | 0 | ||
Total provision for income taxes | $ 1,408 | $ 1,623 | $ 1,166 |
Income Taxes - Income Tax Expen
Income Taxes - Income Tax Expense by Applying Statutory Federal Income Tax Rate (Detail) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax Disclosure [Abstract] | |||
Tax at statutory federal rate | 34.00% | 34.00% | 34.00% |
State tax, net of federal benefit | (0.40%) | (0.40%) | 0.00% |
Other | (4.40%) | (3.70%) | (3.50%) |
Foreign rate differential | 0.50% | (0.20%) | (0.50%) |
Tax credits | 4.50% | 3.20% | 1.60% |
Excess tax benefits related to stock-based compensation | 21.50% | ||
Effect of Tax Cuts and Jobs Act of 2017 | (121.10%) | ||
Change in valuation allowance | 61.40% | (38.40%) | (33.40%) |
Total | (4.00%) | (5.50%) | (1.80%) |
Income Taxes - Tax Effects of T
Income Taxes - Tax Effects of Temporary Differences and Carryforwards That Give Rise to Significant Portions of Deferred Tax Assets (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Income Tax Disclosure [Abstract] | ||
Net operating loss carryforwards | $ 60,999 | $ 60,610 |
Tax credits | 10,198 | 7,655 |
Depreciation | 133 | 26 |
Stock-based compensation | 6,983 | 5,207 |
Accruals and reserves | 7,280 | 7,559 |
Other | 2,525 | 4,671 |
Deferred tax assets | 88,118 | 85,728 |
Valuation allowance | $ (88,118) | $ (85,728) |
Income Taxes - Additional Infor
Income Taxes - Additional Information (Detail) - USD ($) | 12 Months Ended | ||||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | |
Income Taxes [Line Items] | |||||
Tax at statutory federal rate | 34.00% | 34.00% | 34.00% | ||
Increase in valuation allowance | $ 2,400,000 | $ 18,700,000 | $ 23,400,000 | ||
Unrecognized tax benefits | 4,233,000 | 3,384,000 | 3,844,000 | $ 1,962,000 | |
Accrued interest and penalties | 0 | $ 0 | $ 0 | ||
Research and Development Credit Carryforwards [Member] | California state [Member] | |||||
Income Taxes [Line Items] | |||||
Tax credit carry forwards | 5,500,000 | ||||
Federal [Member] | |||||
Income Taxes [Line Items] | |||||
Increase in net operating loss carryforwards | 18,600,000 | ||||
Net operating loss carryforward | $ 260,700,000 | ||||
Net operating loss expiration date | 2,026 | ||||
Federal [Member] | Research and Development Credit Carryforwards [Member] | |||||
Income Taxes [Line Items] | |||||
Tax credit carry forwards | $ 7,700,000 | ||||
State and Local Jurisdiction [Member] | |||||
Income Taxes [Line Items] | |||||
Net operating loss carryforward | $ 101,500,000 | ||||
Net operating loss expiration date | 2,020 | ||||
Scenario Forecast [Member] | |||||
Income Taxes [Line Items] | |||||
Tax at statutory federal rate | 21.00% |
Income Taxes - Summary of Unrec
Income Taxes - Summary of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax Disclosure [Abstract] | |||
Beginning balance | $ 3,384 | $ 3,844 | $ 1,962 |
Increases related to current year tax provisions | 790 | 1,059 | 813 |
Increases related to prior year tax provisions | 193 | 1,069 | |
Decreases related to prior year tax provisions | (134) | (1,519) | |
Ending balance | $ 4,233 | $ 3,384 | $ 3,844 |
Net Loss Per Share - Computatio
Net Loss Per Share - Computation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Earnings Per Share [Abstract] | |||||||||||
Net loss | $ (4,311) | $ (6,230) | $ (11,610) | $ (14,507) | $ (9,825) | $ (3,886) | $ (8,779) | $ (9,288) | $ (36,658) | $ (31,778) | $ (67,431) |
Weighted average shares outstanding | 29,424,360 | 28,492,091 | 26,603,512 | ||||||||
Less: weighted average shares subject to repurchase | (306) | (7,088) | (21,622) | ||||||||
Weighted average shares used to compute basic and diluted net loss per share | 29,664,926 | 29,513,842 | 29,351,414 | 29,159,509 | 28,817,333 | 28,542,760 | 23,381,253 | 28,194,457 | 29,424,054 | 28,485,003 | 26,581,890 |
Net loss per share, basic and diluted | $ (0.15) | $ (0.21) | $ (0.40) | $ (0.50) | $ (0.34) | $ (0.14) | $ (0.31) | $ (0.33) | $ (1.25) | $ (1.12) | $ (2.54) |
Net Loss Per Share Attributable
Net Loss Per Share Attributable to Common Stockholders - Computation of Potentially Dilutive Securities Outstanding Excluded from Computation of Diluted Shares (Detail) - shares | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
Potentially dilutive securities excluded from computation of diluted shares outstanding | 6,860,878 | 6,746,848 | 3,055,448 |
Unreleased Restricted Stock [Member] | |||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
Potentially dilutive securities excluded from computation of diluted shares outstanding | 720,840 | 345,555 | 5,160 |
Options to Purchase Common Stock [Member] | |||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
Potentially dilutive securities excluded from computation of diluted shares outstanding | 2,559,972 | 2,821,227 | 3,050,288 |
Convertible Senior Notes [Member] | |||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
Potentially dilutive securities excluded from computation of diluted shares outstanding | 1,790,033 | 1,790,033 | |
Warrants Related to the Issuance of Convertible Senior Notes [Member] | |||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
Potentially dilutive securities excluded from computation of diluted shares outstanding | 1,790,033 | 1,790,033 |
Net Loss Per Share Attributab69
Net Loss Per Share Attributable to Common Stockholders - Additional Information (Detail) | Dec. 31, 2017$ / shares |
1.75% Convertible Senior Notes due 2021 [Member] | |
Earnings Per Share Diluted [Line Items] | |
Convertible notes, conversion price | $ 96.37 |
Employee Benefit Plan - Additio
Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Postemployment Benefits [Abstract] | ||
Expense for matching contributions | $ 2.2 | $ 1.3 |
Selected Quarterly Financial 71
Selected Quarterly Financial Information - Schedule of Selected Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Quarterly Financial Information Disclosure [Abstract] | |||||||||||
Total revenue | $ 97,963 | $ 82,256 | $ 78,016 | $ 68,439 | $ 70,531 | $ 60,922 | $ 55,400 | $ 41,651 | $ 326,674 | $ 228,504 | $ 69,606 |
Gross profit | 69,512 | 57,940 | 53,873 | 46,368 | 48,839 | 41,687 | 36,558 | 25,987 | 227,693 | 153,071 | 41,486 |
Loss from operations | (2,172) | (4,418) | (9,938) | (13,051) | (6,269) | (1,872) | (5,923) | (9,017) | (29,579) | (23,081) | (62,367) |
Net loss | $ (4,311) | $ (6,230) | $ (11,610) | $ (14,507) | $ (9,825) | $ (3,886) | $ (8,779) | $ (9,288) | $ (36,658) | $ (31,778) | $ (67,431) |
Net loss per share, basic and diluted | $ (0.15) | $ (0.21) | $ (0.40) | $ (0.50) | $ (0.34) | $ (0.14) | $ (0.31) | $ (0.33) | $ (1.25) | $ (1.12) | $ (2.54) |
Shares used in computing net loss per common share, basic and diluted | 29,664,926 | 29,513,842 | 29,351,414 | 29,159,509 | 28,817,333 | 28,542,760 | 23,381,253 | 28,194,457 | 29,424,054 | 28,485,003 | 26,581,890 |