Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 16,635	$ 17,223
Short-term investments	28,726	55,002
Accounts receivable, net	12,903	12,436
Inventory	11,699	5,444
Prepaid expenses and other	4,602	5,242
Total current assets	74,565	95,347
Restricted cash	143	143
Deferred offering costs	137	0
Property and equipment, net	7,371	6,366
Other assets	788	892
Total assets	83,004	102,748
Current liabilities:
Accounts payable	2,561	3,380
Accrued liabilities	7,348	10,403
Deferred revenue, current portion	5,635	4,627
Deferred rent, current portion	202	147
Long-term debt, current portion	259	251
Total current liabilities	16,005	18,808
Deferred revenue, net of current portion	6,214	7,135
Deferred rent, net of current portion	2,273	1,317
Long-term debt, net of current portion	31,326	30,675
Total liabilities	$ 55,818	$ 57,935
Commitment and contingencies
Stockholders' equity:
Preferred stock, $0.0001 par value, 15,000 shares authorized; none issued	$ 0	$ 0
Common stock, $0.0001 par value, 150,000 shares authorized; 19,506 and 18,272 shares issued and outstanding at September 30, 2015 and December 31, 2014, respectively	2	2
Additional paid-in-capital	240,823	221,724
Accumulated other comprehensive loss	(4)	(43)
Accumulated deficit	(213,635)	(176,870)
Total stockholders' equity	27,186	44,813
Total liabilities and stockholders' equity	$ 83,004	$ 102,748