Quarterly Financial Information - Summary of Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Cash, cash equivalents and short-term investments	$ 29,723	$ 29,311	$ 29,430	$ 26,594	$ 26,390	$ 25,221	$ 24,131	$ 22,976
Accounts receivable	19,009	15,560	15,418	13,490	13,626	11,749	11,235	13,130
Total current assets	49,312	45,395	45,557	40,799	40,733	37,427	36,941	37,926
Total assets	55,258	51,593	51,813	47,161	47,241	43,942	43,428	44,601
Third-party software fees payable	11,789	10,184	12,361	10,793	12,247	9,941	9,528	11,424
Accounts payable	188	285	191	211	165	171	61	187
Accrued compensation	2,390	2,333	2,173	1,738	2,106	1,843	2,160	1,722
Other accrued expenses	1,277	1,320	1,501	1,374	1,539	1,607	1,661	1,711
Total current liabilities	17,077	15,120	17,147	14,951	17,044	15,066	15,418	17,751
Common stock	133,331	132,601	131,962	131,410	131,071	130,709	130,449	129,946
Accumulated deficit	(95,555)	(96,695)	(97,940)	(99,825)	(101,648)	(103,044)	(103,735)	(104,385)
Total shareholders' equity	36,907	35,077	33,189	30,662	28,577	26,940	26,086	24,879	$ 24,671
Total liabilities and shareholders' equity	$ 55,258	$ 51,593	$ 51,813	$ 47,161	$ 47,241	$ 43,942	$ 43,428	$ 44,601