v3.19.3.a.u2
Consolidated Statements of Cash Flows - USD ($)
shares in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Operating activities      
Net loss $ (124,827) $ (128,154) $ (137,628)
Adjustments to reconcile net loss to net cash used in operating activities:      
Depreciation and amortization 7,730 7,501 7,143
Non-cash lease expense 7,748    
Impairment of assets 1,671 1,544 576
Stock-based compensation 28,624 14,198 11,402
Inventory excess adjustments 321 265 502
Provision for doubtful accounts 1,141 (41) 143
Premium amortization and discount accretion on investment securities 945 238 857
(Gain) loss realized on investment securities (16) 43 64
(Gain) loss on sales of property and equipment   (12) 12
Loss (gain) from changes in fair value of warrants   4,118 (1,148)
Interest accrued for borrowings and claims related settlement   2,172 488
Amortization of debt discount 457 391 154
Other non-cash (benefits) (51)    
Gain on disposal of business (14,388)    
Changes in operating assets and liabilities      
Accounts receivable 2,418 (18,093) 6,315
Inventory 917 (4,900) (3,086)
Prepaid expenses and other current assets (13,956) 2,643 (1,515)
Other assets (9,099) 335 600
Accounts payable (6,262) 3,781 217
Accrued compensation 3,419 3,069 (1,467)
Other accrued liabilities 8,606 (1,820) 14,919
Deferred revenue 40,848 42,769 846
Deferred rent, net of current portion   (628) 1,452
Other long-term liabilities 310   1,329
Net cash used in operating activities (63,444) (70,581) (97,825)
Investing activities      
Purchases of investments (446,626) (170,268) (272,819)
Proceeds from sale of investments 1,666 37,387 65,270
Proceeds from maturity of investments 173,900 131,600 231,200
Net proceeds from disposal of business 9,675    
Purchases of property and equipment, net (4,968) (3,880) (9,867)
Net cash (used in) provided by investing activities (266,353) (5,161) 13,784
Financing activities      
Proceeds from exercise of stock options 13,041 13,331 2,315
Proceeds from issuance of common stock under employee stock purchase plan 4,323 3,617 3,344
Proceeds from equity offering, net of issuance costs 323,410 96,777  
Borrowings under long-term debt facility     75,000
Payment for debt issuance costs on long-term debt facility     287
Net cash provided by financing activities 340,774 113,725 80,372
Net increase (decrease) increase in cash, cash equivalents and restricted cash 10,977 37,983 (3,669)
Cash, cash equivalents and restricted cash, beginning of period 51,004 13,021 16,690
Cash, cash equivalents and restricted cash, end of period 61,981 51,004 13,021
Supplemental disclosure of cash flow information:      
Cash paid for income taxes 2,154 332 177
Cash paid for interest 12,455 7,914 3,568
Non-cash investing and financing activities:      
Purchases of property and equipment in accounts payable and accruals $ 3,706 $ 268 $ 447
Issuance of common stock for exercise of warrants   6,762  
Issuance of common stock for lender's commitment to debt financing     2,448