CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 222,031	$ 38,972
Accounts receivable, net of allowance for doubtful accounts of $400 and $332 at June 30, 2014 and December 31, 2013, respectively	44,060	42,185
Prefunded coupons cash deposits	1,497	920
Prepaid expenses and other current assets	4,252	3,100
Total current assets	271,840	85,177
Property and equipment, net	27,820	29,942
Intangible assets, net	3,597	1,813
Goodwill	17,880	9,887
Deferred tax assets	900	195
Other assets	3,728	7,222
Total assets	325,765	134,236
Current liabilities:
Accounts payable	7,703	5,589
Accrued compensation and benefits	10,490	13,721
Other current liabilities	14,790	13,699
Prefunded coupons cash obligations	1,497	920
Deferred revenues	7,740	6,751
Debt obligations	7,500	7,500
Debt obligations, related party	15,999	15,577
Total current liabilities	65,719	63,757
Other non-current liabilities	569	1,046
Deferred rent	940	1,222
Deferred tax liabilities	900	195
Total liabilities	68,128	66,220
Commitments and contingencies (Note 14)
Redeemable convertible preferred stock, $0.00001 par value—no shares authorized, issued and outstanding, and aggregate liquidation preference of $0 at June 30, 2014; 50,437,000 shares authorized and 41,529,721 shares issued and outstanding, and aggregate liquidation preference of $282,990 at December 31,2013		270,262
Stockholders’ equity (deficit):
Preferred stock, $0.00001 par value—10,000,000 shares authorized and no shares issued or outstanding at June 30, 2014; no shares authorized, issued or outstanding at December 31, 2013
Common stock, $0.00001 par value—250,000,000 shares authorized and 82,419,992 shares issued and 77,575,086 outstanding at June 30, 2014; 96,000,000 shares authorized and 25,934,206 shares issued and 21,089,300 outstanding at December 31, 2013	1
Additional paid-in capital	509,179	28,403
Treasury stock, at cost	(61,935)	(61,935)
Accumulated other comprehensive income (loss)	82	37
Accumulated deficit	(189,690)	(168,751)
Total stockholders’ equity (deficit)	257,637	(202,246)
Total liabilities, redeemable convertible preferred stock and stockholders’ equity (deficit)	$ 325,765	$ 134,236