Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 121,882	$ 44,247
Accounts receivable, net of allowances	16,961	14,106
Prepaid expenses and other current assets	3,595	2,379
Total current assets	142,438	60,732
Property and equipment, net	10,918	5,617
Goodwill	9,537	9,537
Intangible assets, net	2,645	2,734
Other assets	642	536
Total assets	166,180	79,156
Current liabilities:
Accounts payable	4,602	2,217
Accrued expenses and other current liabilities	13,052	8,945
Deferred revenue	30,566	20,642
Current portion of credit facility	1,297	582
Total current liabilities	49,517	32,386
Credit facility, net of current portion	5,316	3,058
Deferred rent	1,370	148
Total liabilities	56,203	35,592
Commitments and contingencies (Note 6)
Stockholder's equity:
Convertible preferred stock		119,121
Common stock	4
Additional paid-in capital	213,931	6,499
Accumulated other comprehensive income	157	145
Accumulated deficit	(104,115)	(82,201)
Total stockholders' equity	109,977	43,564
Total liabilities and stockholders' equity	$ 166,180	$ 79,156