Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 28,817	$ 19,240
Accounts receivable, net of allowances of $421 at June 30, 2017 and December 31, 2016	7,802	5,924
Inventories	806	825
Prepaid expenses and other current assets	2,965	1,238
Total current assets	40,390	27,227
Restricted cash	1,576	1,624
Marketable securities	1,305	1,142
Property and equipment, net	2,969	2,155
Goodwill	3,241	3,241
Other non-current assets	303	259
Total assets	49,784	35,648
Current liabilities:
Accounts payable	3,633	4,232
Accrued compensation	2,920	4,314
Other accrued liabilities	2,647	2,111
Deferred revenue	4,027	1,710
Total current liabilities	13,227	12,367
Deferred revenue, net of current portion	2,653	1,066
Financing obligation, net of current portion	419	0
Other long-term liabilities	2,848	3,116
Total liabilities	19,147	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; 48,324 shares and 41,255 shares issued and outstanding at June 30, 2017 and December 31, 2016, respectively	5	4
Additional paid-in capital	336,339	311,164
Accumulated other comprehensive income (loss)	102	0
Accumulated deficit	(305,809)	(292,069)
Total stockholders' equity	30,637	19,099
Total liabilities and stockholders' equity	$ 49,784	$ 35,648