CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 16,810	$ 23,354
Short-term investments	56,231	50,439
Accounts receivable, net	15,375	14,627
Prepaid expenses and other current assets	1,390	1,403
Total current assets	89,806	89,823
Property and equipment, net	484	417
Goodwill	14,240	14,240
Intangible assets, net	2,095	2,363
Other assets	1,159	1,144
Total assets	107,784	107,987
Current liabilities:
Accounts payable	728	1,625
Accrued compensation	4,068	2,792
Other accrued liabilities	4,169	3,029
Short-term deferred revenue	2,573	2,619
Total current liabilities	11,538	10,065
Long-term deferred revenue	75	72
Other long-term liabilities	2,131	2,129
Total liabilities	13,744	12,266
Commitments and contingencies (Note 4)
Stockholders' equity:
Common stock; par value $0.0001, 150,000,000 shares authorized; 55,537,526 issued and 54,344,928 outstanding at March 31, 2015; 55,457,001 issued and 54,264,483 outstanding at December 31, 2014	5	5
Additional paid-in capital	262,964	262,253
Treasury stock	(5,036)	(5,036)
Accumulated other comprehensive loss	(1,989)	(2,028)
Accumulated deficit	(161,904)	(159,473)
Total stockholders' equity	94,040	95,721
Total liabilities and stockholders' equity	$ 107,784	$ 107,987