Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 11,211	$ 15,256
Restricted cash, current portion	45	1,092
Short-term investments	135,017	130,860
Accounts receivable, net of allowance of $1,795 in 2017 and $1,890 in 2016	7,342	13,396
Inventory	9,188	6,414
Prepaid expenses and other current assets	6,437	7,097
Total current assets	169,240	174,115
Property and equipment, net	30,417	32,289
Restricted cash, long term portion	342	342
Other assets	4,057	3,934
Total assets	204,056	210,680
Current liabilities:
Accounts payable	3,753	11,479
Accrued compensation	9,428	11,067
Other accrued liabilities	23,022	19,879
Deferred revenue	1,041	574
Short-term debt financing	50,097	49,624
Warrants	4,189	3,792
Total current liabilities	91,530	96,415
Long-term debt financing	73,202
Deferred rent, net of current portion	9,140	7,789
Total liabilities	173,872	104,204
Commitments and contingencies (Note 6)
Stockholders' equity:
Common stock, $0.0001 par value: 750,000 shares authorized at both September 30, 2017 and December 31, 2016, respectively; 53,708 and 52,665 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively	6	5
Additional paid in capital	467,234	453,044
Accumulated deficit	(436,660)	(345,848)
Accumulated other comprehensive loss	(396)	(725)
Total stockholders' equity	30,184	106,476
Total liabilities and stockholders' equity	$ 204,056	$ 210,680