Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 22,916	$ 33,047
Short-term investments		3,061
Restricted cash		121
Accounts receivable, net of allowance of $181 and $461 at December 31, 2014 and 2013, respectively	21,463	21,560
Prepaid expenses	3,127	2,895
Deferred tax asset	109	125
Other current assets	1,215	1,116
Total current assets	48,830	61,925
Property and equipment, net	10,372	8,795
Intangible assets, net	16,898	8,668
Goodwill	50,776	22,018
Restricted cash, net of current portion	201	201
Other assets	507	1,519
Total assets	127,584	103,126
Current liabilities:
Accounts payable	1,618	3,067
Accrued expenses	11,722	14,528
Capital lease liability	1,159
Deferred revenue	29,640	23,571
Total current liabilities	44,139	41,166
Deferred revenue, net of current portion	64	247
Other liabilities	2,618	1,333
Total liabilities	46,821	42,746
Commitments and contingencies (Note 6)
Stockholders' equity:
Undesignated preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued
Common stock, $0.001 par value; 100,000,000 shares authorized; 32,424,554 and 29,034,919 shares issued and outstanding at December 31, 2014 and 2013, respectively	32	29
Additional-paid-in-capital	214,524	176,928
Accumulated other comprehensive loss	(776)	(453)
Accumulated deficit	(133,017)	(116,124)
Total stockholders' equity	80,763	60,380
Total liabilities and stockholders' equity	$ 127,584	$ 103,126