Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 22,938	$ 29,726
Short-term marketable securities	105,042	73,934
Accounts receivable (net of allowance for doubtful accounts; 2015 - $3,574, 2014 - $3,628)	34,979	34,916
Prepaid expenses and other current assets	12,085	9,944
Total current assets	175,044	148,520
Property and equipment, net	25,171	21,860
Other assets	1,755	15,541
Total assets	201,970	185,921
Current liabilities:
Accounts payable	7,952	6,987
Accrued compensation and employee benefits	16,388	17,708
Accrued license fees	2,249	2,656
Accrued expenses and other current liabilities	15,510	10,444
Deferred revenues	268	335
Other current liabilities	208	208
Total current liabilities	42,575	38,338
Other liabilities	2,667	2,070
Commitments
Stockholders' equity:
Common stock	3	3
Additional paid- in capital	373,674	370,496
Accumulated other comprehensive income (loss)	17,515	(15)
Accumulated deficit	(204,354)	(194,861)
Treasury stock, at cost	30,110	30,110
Total stockholders' equity	156,728	145,513
Total liabilities and stockholders' equity	$ 201,970	$ 185,921