Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 14,918	$ 23,273
Restricted cash, current	883	0
Accounts receivable, net of allowances of $421 at September 30, 2016 and December 31, 2015	11,965	7,329
Inventories	1,076	992
Prepaid expenses and other current assets	1,264	1,245
Total current assets	30,106	32,839
Restricted cash	783	787
Marketable securities	1,527	1,549
Property and equipment, net	2,301	3,109
Intangible assets, net	281	2,812
Goodwill	3,241	3,241
Other non-current assets	272	310
Total assets	38,511	44,647
Current liabilities:
Accounts payable	2,123	3,399
Accrued compensation	3,024	3,331
Other accrued liabilities	2,339	2,013
Deferred revenue	4,221	6,098
Total current liabilities	11,707	14,841
Deferred revenue, net of current portion	745	3,120
Lease incentive obligation, net of current portion	992	1,310
Other long-term liabilities	2,230	2,497
Liabilities	15,674	21,768
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; 41,218 shares and 40,343 shares issued and outstanding at September 30, 2016 and December 31, 2015, respectively	4	4
Additional paid-in capital	309,258	305,981
Accumulated other comprehensive income	384	405
Accumulated deficit	(286,809)	(283,511)
Total stockholders' equity	22,837	22,879
Total liabilities and stockholders' equity	$ 38,511	$ 44,647