v3.7.0.1
Condensed Consolidated Statements of Cash Flows - USD ($)
$ in Thousands
 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Operating Activities    
Net loss $ (63,693) $ (31,841)
Adjustments to reconcile net loss to net cash used in operating activities:    
Depreciation and amortization 3,620 2,428
Stock-based compensation 5,420 5,292
Premium amortization and discount accretion on investment securities 515 761
Inventory excess adjustments 187  
Loss on disposal of property and equipment 12  
Impairment of assets 576 20
Non-cash interest accrual 399 237
Loss (gain) on investments 47 (112)
(Gain) loss from changes in fair value of warrants (320) 306
Provision for doubtful accounts (240) 479
Changes in operating assets and liabilities    
Accounts receivable 6,530 (789)
Inventory (1,132) (800)
Prepaid expenses and other current assets 1,349 (296)
Restricted cash 328 (32)
Other assets 223 (532)
Accounts payable 2,028 2,150
Accrued compensation (2,961) 543
Other accrued liabilities 7,493 (156)
Deferred revenue 96 188
Deferred rent, net of current portion 1,457 1,964
Net cash used in operating activities (38,066) (20,190)
Investing Activities    
Purchases of investments (4,219) (30,118)
Proceeds from sale of investments 36,791 16,766
Proceeds from maturity of investments 3,000 18,000
Proceeds from sale of property and equipment   225
Purchases of property and equipment, net (8,066) (7,311)
Net cash provided by (used in) investing activities 27,506 (2,438)
Financing Activities    
Proceeds from exercise of stock options 939 2,268
Proceeds from issuance of common stock under employee stock purchase plan 1,503 970
Borrowings under credit facility   8,000
Repayment under credit facility   (1,000)
Net cash provided by financing activities 2,442 10,238
Net decrease in cash (8,118) (12,390)
Cash at beginning of period 15,256 28,947
Cash at end of period $ 7,138 $ 16,557