Condensed Consolidated Balance Sheets (Unaudited) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Current assets:    
Cash and cash equivalents $ 277,821 $ 292,325
Short-term investments 572,809 520,844
Accounts receivable, net of allowance for doubtful accounts of $847 and $663 as of March 31, 2015 and December 31, 2014, respectively 29,263 23,189
Income tax receivable 1,395 1,900
Prepaid expenses and other current assets 32,763 17,913
Deferred tax assets 9,389 8,774
Total current assets 923,440 864,945
Property and equipment, net 57,384 56,173
Goodwill 470,656 493,671
Intangible assets, net 64,754 70,456
Non-marketable investments 37,506 35,285
Deferred tax assets 1,326 1,545
Other non-current assets 6,990 8,053
Total assets 1,562,056 1,530,128
Current liabilities:    
Accounts payable 11,585 8,281
Income tax payable 1,593 1,344
Accrued expenses 49,481 50,255
Deferred revenue 190,364 170,522
Total current liabilities 253,023 230,402
Convertible senior notes, net 320,690 316,181
Deferred revenue, less current portion 3,007 3,179
Deferred tax liabilities 25,978 26,624
Other non-current liabilities 17,979 12,192
Total liabilities 620,677 588,578
Commitments and contingencies (see Note 6)      
Redeemable noncontrolling interests (see Note 8) 9,930 9,742
Stockholders' equity    
Common stock: $0.0001 par value; 350,000,000 shares authorized; 94,798,802 and 94,515,344 shares issued and outstanding as of March 31, 2015 and December 31, 2014, respectively 9 9
Additional paid-in capital 1,038,605 1,022,586
Accumulated other comprehensive loss (42,949) (28,053)
Accumulated deficit (64,216) (62,734)
Total stockholders' equity 931,449 931,808
Total liabilities, redeemable noncontrolling interests and stockholders' equity $ 1,562,056 $ 1,530,128