Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 84,253	$ 94,072
Short-term investments	89,568	92,749
Accounts receivable, net of allowance for doubtful accounts of $379 and $54 at June 30, 2012 and December 31, 2011, respectively	39,839	47,048
Deferred tax assets	12,409	12,968
Other current assets	7,451	4,435
Total current assets	233,520	251,272
Long-term assets:
Property and equipment, net	4,708	4,221
Long-term investments	20,405	5,000
Restricted cash	959	959
Intangible assets, net	7,682	8,842
Goodwill	20,207	17,276
Other long-term assets	7,310	3,386
Total long-term assets	61,271	39,684
Total assets	294,791	290,956
Current liabilities:
Accounts payable and accrued expenses	12,272	14,999
Notes payable and bank loans, current portion	475	891
Deferred revenue, current portion	46,816	55,372
Total current liabilities	59,563	71,262
Convertible senior notes	84,048	81,737
Notes payable and bank loans	448	461
Deferred revenue	1,978	1,764
Deferred tax liabilities	3,973	1,433
Other long-term liabilities	1,149	1,056
Total liabilities	151,159	157,713
Commitments and contingencies (Note 9)
Stockholders' equity:
Preferred stock, $0.01 par value per share; 5,000,000 shares authorized at June 30, 2012 and December 31, 2011; no shares issued and outstanding at June 30, 2012 and December 31, 2011
Common stock, par value $0.01 per share; 100,000,000 shares authorized at June 30, 2012 and December 31, 2011; 27,581,558 and 27,106,393 shares issued and outstanding at June 30, 2012 and December 31, 2011, respectively	276	271
Additional paid-in capital	198,710	191,714
Accumulated other comprehensive loss	(3,226)	(2,557)
Accumulated deficit	(52,128)	(56,185)
Total stockholders' equity	143,632	133,243
Total liabilities and stockholders' equity	$ 294,791	$ 290,956