Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents (including restricted cash of $200 at December 31, 2012)	$ 204,865	$ 201,989
Marketable securities (including restricted securities of $222 and $57 at June 30, 2013 and December 31, 2012, respectively)	326,077	235,592
Accounts receivable, net of reserves of $4,632 and $3,807 at June 30, 2013 and December 31, 2012, respectively	237,286	218,777
Prepaid expenses and other current assets	70,734	51,604
Deferred income tax assets	20,422	20,422
Total current assets	859,384	728,384
Property and equipment, net	405,653	345,091
Marketable securities (including restricted securities of $50 and $43 at June 30, 2013 and December 31, 2012, respectively)	587,470	657,659
Goodwill	729,386	731,325
Acquired intangible assets, net	68,562	84,554
Deferred income tax assets	14,527	13,803
Other assets	60,288	39,811
Total assets	2,725,270	2,600,627
Current liabilities:
Accounts payable	50,370	43,291
Accrued expenses and other current liabilities	143,652	133,087
Deferred revenue	32,019	26,291
Accrued restructuring	533	275
Total current liabilities	226,574	202,944
Other liabilities	47,928	49,364
Deferred revenue	2,895	2,565
Total liabilities	277,397	254,873
Commitments, contingencies and guarantees (Note 15)
Stockholders’ equity:
Preferred stock, $0.01 par value; 5,000,000 shares authorized; 700,000 shares designated as Series A Junior Participating Preferred Stock; no shares issued or outstanding	0	0
Common stock, $0.01 par value; 700,000,000 shares authorized; 202,712,865 shares issued and 178,115,006 shares outstanding at June 30, 2013 and 200,199,536 shares issued and 177,782,814 shares outstanding at December 31, 2012	2,045	2,015
Additional paid-in capital	5,256,348	5,195,543
Accumulated other comprehensive loss	(10,955)	(1,640)
Treasury stock, at cost, 24,597,859 shares at June 30, 2013 and 22,416,722 shares at December 31, 2012	(707,245)	(624,462)
Accumulated deficit	(2,092,320)	(2,225,702)
Total stockholders’ equity	2,447,873	2,345,754
Total liabilities and stockholders’ equity	$ 2,725,270	$ 2,600,627