Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 23,826	$ 19,240
Accounts receivable, net of allowances of $34 at September 30, 2017 and $421 at December 31, 2016	7,906	5,924
Inventories	849	825
Prepaid expenses and other current assets	2,443	1,238
Total current assets	35,024	27,227
Restricted cash	1,536	1,624
Marketable securities	1,163	1,142
Property and equipment, net	2,810	2,155
Goodwill	3,241	3,241
Other non-current assets	327	259
Total assets	44,101	35,648
Current liabilities:
Accounts payable	4,474	4,232
Accrued compensation	3,795	4,314
Other accrued liabilities	4,664	2,111
Deferred revenue	4,141	1,710
Total current liabilities	17,074	12,367
Deferred revenue, net of current portion	1,839	1,066
Financing obligation, net of current portion	360	0
Other long-term liabilities	2,736	3,116
Total liabilities	22,009	16,549
Commitments and contingencies (Note 10)
Stockholders' equity:
Preferred stock, $0.0001 par value per share; 5,000 shares authorized; none issued and outstanding	0	0
Common stock, $0.0001 par value per share; 100,000 shares authorized; 48,343 shares and 41,255 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively	5	4
Additional paid-in capital	338,110	311,164
Accumulated other comprehensive income	13	0
Accumulated deficit	(316,036)	(292,069)
Total stockholders' equity	22,092	19,099
Total liabilities and stockholders' equity	$ 44,101	$ 35,648