Quarterly Financial Information - Summary of Condensed Consolidated Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Cash, cash equivalents and short-term investments	$ 26,390	$ 25,221	$ 24,131	$ 22,976	$ 20,805	$ 21,289	$ 19,902	$ 19,422
Accounts receivable	13,626	11,749	11,235	13,130	15,893	12,811	13,614	12,639
Total current assets	40,743	37,427	36,941	37,926	39,023	35,560	35,080	33,378
Total assets	47,241	43,942	43,428	44,601	44,648	41,309	43,517	41,978
Third-party software fees payable	12,247	9,941	9,528	11,424	12,746	11,055	10,090	8,712
Accounts payable	165	171	61	187	634	778	510	276
Accrued compensation	2,106	1,843	2,160	1,722	2,383	1,986	2,242	1,862
Other accrued expenses	1,539	1,607	1,661	1,711	1,249	1,332	1,772	1,490
Total current liabilities	17,044	15,066	15,418	17,751	19,189	16,225	15,486	13,338
Common stock	131,071	130,709	130,449	129,946	129,423	129,215	128,991	128,730
Accumulated deficit	(101,648)	(103,044)	(103,735)	(104,385)	(103,993)	(103,968)	(100,403)	(99,598)
Total shareholders' equity	28,577	26,940	26,086	24,879	24,671	24,456	27,709	28,301	29,005
Total liabilities and shareholders' equity	$ 47,241	$ 43,942	$ 43,428	$ 44,601	$ 44,648	$ 41,309	$ 43,517	$ 41,978