Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 22,163	$ 23,273
Accounts receivable, net of allowances of $421 at March 31, 2016 and December 31, 2015	4,352	7,329
Inventories	1,021	992
Prepaid expenses and other current assets	1,239	1,245
Total current assets	28,775	32,839
Restricted cash	787	787
Marketable securities	1,459	1,549
Property and equipment, net	2,756	3,109
Intangible assets, net	1,968	2,812
Goodwill	3,241	3,241
Other non-current assets	202	310
Total assets	39,188	44,647
Current liabilities:
Accounts payable	2,850	3,399
Accrued compensation	4,305	3,331
Other accrued liabilities	3,224	2,013
Deferred revenue	6,105	6,098
Total current liabilities	16,484	14,841
Deferred revenue, net of current portion	2,929	3,120
Lease incentive obligation, net of current portion	1,204	1,310
Other long-term liabilities	$ 2,458	$ 2,497
Commitments and contingencies (Note 10)
Stockholders' equity:
Preferred stock, $0.0001 par value; 5,000 shares authorized, none issued and outstanding	$ 0	$ 0
Common stock, $0.0001 par value; 100,000 shares authorized at March 31, 2016 and December 31, 2015; shares issued of 41,081 and 40,636 at March 31, 2016 and December 31, 2015, respectively; and shares outstanding of 40,788 and 40,343 at March 31, 2016 and December 31, 2015, respectively	4	4
Additional paid-in capital	306,279	305,981
Accumulated other comprehensive income	315	405
Accumulated deficit	(290,485)	(283,511)
Total stockholders' equity	16,113	22,879
Total liabilities and stockholders' equity	$ 39,188	$ 44,647