v3.6.0.2
Consolidated Statements of Cash Flows - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Operating Activities      
Net loss $ (95,765) $ (70,275) $ (5,152)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:      
Depreciation and amortization 6,176 5,535 5,148
Amortization of premium on investment securities 1,445 288  
Gain realized on investment securities (191)    
Impairment of assets 2,138 1,557  
Inventory excess adjustments 2,110    
Stock based compensation 10,601 7,326 5,157
Loss from changes in fair value of warrants 143 1,481 1,664
Provision for doubtful accounts 984 529 349
Non-cash interest accrual 533    
(Gain) loss on sales of property and equipment   (2) 11
Amortization of debt discount   28  
Gain from change in fair value of long term debt   (964) (118)
Loss on debt extinguishment   7,313  
Changes in operating assets and liabilities      
Accounts receivable (8,518) (450) 341
Inventory (431) 2,929 (890)
Prepaid expenses and other current assets (2,077) (3,797) (137)
Restricted cash 150 (273)  
Other assets (2,812) (1,041) (24)
Accounts payable 1,256 1,354 (2,430)
Income taxes payable     (15)
Accrued compensation 2,515 2,572 2,994
Other accrued liabilities 7,411 8,026 4,450
Deferred revenue 430 32 (858)
Net cash (used in) provided by operating activities (73,902) (37,832) 10,490
Investing Activities      
Purchases of investments (53,522) (203,290)  
Proceeds from sale of investments 59,185    
Proceeds from maturity of investments 64,500    
Proceeds from sale of property and equipment   463 15
Purchases of property and equipment, net (23,136) (7,852) (9,957)
Net cash (used in) investing activities 47,027 (210,679) (9,942)
Financing Activities      
Proceeds from issuance of common stock, net of issuance costs   180,001 170
Proceeds from exercise of stock options 3,595 1,258  
Proceeds from issuance of common stock under employee stock purchase plan 2,589    
Proceeds from issuance of preferred stock, net     55,413
Borrowings under credit facility 8,000    
Repayment under credit facility (1,000)    
Costs paid for loan   (6)  
Proceeds from short-term financing   42,000  
Proceeds from equipment financing     5,105
Repayments of equipment financing   (5,850) (2,480)
Repayments of secured financings   (20,000)  
Proceeds from collection of officer receivable   192  
Payment to lender for debt extinguishment   (7,313)  
Change in restricted cash     (415)
Deferred offering costs     (1,661)
Net cash provided by financing activities 13,184 190,282 56,132
Net (decrease) increase in cash (13,691) (58,229) 56,680
Cash at beginning of period 28,947 87,176 30,496
Cash at end of period 15,256 28,947 87,176
Supplemental disclosure of cash flow information:      
Cash paid for interest   2,060 2,063
Purchases of property and equipment through accounts payable and accruals $ 5,204 765 $ 3,223
Conversion of convertible preferred stock to common stock   $ 240,585