Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 32,494	$ 33,279
Short-term marketable securities	73,209	72,071
Accounts receivable (net of allowance for doubtful accounts; 2014 - $2,119, 2013 - $1,907)	31,771	29,446
Prepaid expenses and other current assets	9,014	10,196
Total current assets	146,488	144,992
Property and equipment, net	17,342	18,290
Other assets	14,120	13,752
Total assets	177,950	177,034
Current liabilities:
Accounts payable	5,560	5,160
Accrued compensation	14,213	12,776
Accrued license fees	2,313	2,554
Accrued expenses and other current liabilities	9,863	8,464
Deferred revenues	273	586
Other current liabilities	192	292
Total current liabilities	32,414	29,832
Other liabilities	2,083	2,221
Commitments and contingencies
Stockholders' equity:
Common stock	3	3
Additional paid-in capital	355,889	345,345
Accumulated other comprehensive income	3	12
Accumulated deficit	(182,332)	(170,269)
Treasury stock, at cost	(30,110)	(30,110)
Total stockholders' equity	143,453	144,981
Total liabilities and stockholders' equity	$ 177,950	$ 177,034