Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 33,427	$ 22,760
Accounts receivable, net of allowance for doubtful accounts of $672 as of December 31, 2015 and $669 as of December 31, 2014	21,685	33,578
Advance billings	1,639	4,653
Inventories	50,020	40,579
Prepaid expenses and other current assets	6,057	9,767
Total current assets	112,828	111,337
Property and equipment, net	8,236	7,534
Restricted cash	1,811	1,993
Other assets	438	623
Total assets	123,313	121,487
Current liabilities:
Accounts payable	16,912	22,434
Accrued compensation and benefits	4,707	4,601
Deferred revenues, current	5,144	9,110
Other current liabilities	6,195	6,630
Total current liabilities	32,958	42,775
Deferred revenues, non-current	375	1,160
Other liabilities	2,456	2,442
Total liabilities	$ 35,789	$ 46,377
Commitments and contingencies (Note 7)
Stockholders' equity:
Preferred stock, 2,000 shares authorized; none issued and outstanding	$ 0	$ 0
Common stock, par value $0.001, 120,000 shares authorized; 79,853 shares issued and 75,443 shares outstanding as of December 31, 2015; 78,267 shares issued and 74,009 shares outstanding as of December 31, 2014	80	78
Additional paid-in capital	692,407	687,871
Accumulated other comprehensive income	16,289	18,171
Treasury stock, 4,410 shares as of December 31, 2015 and 4,258 shares as of December 31, 2014	(38,640)	(38,083)
Accumulated deficit	(582,612)	(592,927)
Total stockholders' equity	87,524	75,110
Total liabilities and stockholders' equity	$ 123,313	$ 121,487