Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 33,999	$ 32,533
Short-term marketable securities	64,602	62,410
Accounts receivable (net of allowance for doubtful accounts; 2016—$4,260, 2015—$3,988)	33,682	37,164
Prepaid expenses and other current assets	12,066	10,843
Total current assets	144,349	142,950
Property and equipment, net	39,465	39,746
Other assets	8,137	1,921
Total assets	191,951	184,617
Current liabilities:
Accounts payable	5,411	8,585
Accrued compensation and employee benefits	24,675	22,239
Accrued license fees		2,287
Accrued expenses and other current liabilities	13,599	8,922
Deferred revenues	28	431
Other current liabilities	231	208
Total current liabilities	43,944	42,672
Other liabilities	3,606	2,410
Commitments and contingencies
Stockholders' equity:
Common stock	3	3
Additional paid- in capital	415,144	395,059
Accumulated other comprehensive income	2,804	2,752
Accumulated deficit	(243,440)	(228,169)
Treasury stock, at cost	(30,110)	(30,110)
Total stockholders' equity	144,401	139,535
Total liabilities and stockholders' equity	$ 191,951	$ 184,617