Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 33,674	$ 12,620
Restricted cash, current portion	5,674	59
Short-term investments	80,023	106,247
Accounts receivable, net of allowance of $1,881 in 2018 and $2,000 in 2017	50,326	44,089
Inventory	11,911	8,998
Prepaid expenses and other current assets	5,915	8,612
Total current assets	187,523	180,625
Property and equipment, net	26,878	29,667
Restricted cash, long term portion	342	342
Other assets	3,912	3,979
Total assets	218,655	214,613
Current liabilities:
Accounts payable	8,608	8,529
Accrued compensation	9,933	9,599
Other accrued liabilities	31,523	33,257
Deferred revenue, current portion	1,443	1,420
Short-term debt financing	50,125	50,112
Warrants	2,751	2,644
Total current liabilities	104,383	105,561
Long-term debt financing	73,138	73,065
Deferred rent, net of current portion	9,548	9,241
Deferred revenue, long-term	35,462
Other long-term liabilities		1,329
Total liabilities	222,531	189,196
Commitments and contingencies (Note 7)
Stockholders' equity (deficit):
Common stock, $0.0001 par value: 750,000 shares authorized at both March 31, 2018 and December 31, 2017, respectively; 54,251 and 54,040 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively	6	6
Additional paid in capital	476,270	472,552
Accumulated deficit	(479,248)	(446,375)
Accumulated other comprehensive loss	(904)	(766)
Total stockholders' (deficit) equity	(3,876)	25,417
Total liabilities and stockholders' equity (deficit)	$ 218,655	$ 214,613