Selected Quarterly Financial Information (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
Revenue:
License and subscription revenue	$ 22,918	$ 20,713	$ 20,487	$ 22,275	$ 23,149	$ 23,195	$ 21,399	$ 21,697	$ 21,231	$ 20,127	$ 18,587	$ 19,480	$ 86,393	$ 89,440		$ 79,425
Maintenance on perpetual licenses	10,709	9,926	9,497	10,064	10,035	9,600	9,128	9,491	9,301	9,166	8,581	7,814	40,196	38,254		34,862
Content	2,505	2,373	2,418	2,568	2,991	2,919	3,032	3,543	4,270	4,248	4,272	4,048	9,864	12,485		16,838
Professional services and other	10,343	7,865	6,634	7,231	8,019	4,785	4,835	4,708	4,960	2,710	2,286	3,258	32,073	22,347		13,214
Total revenue	46,475	40,877	39,036	42,138	44,194	40,499	38,394	39,439	39,762	36,251	33,726	34,600	168,526	162,526		144,339
Cost of revenue:
Cost of revenue	12,642	9,662	10,580	11,907	11,961	9,839	10,017	9,878	9,501	8,349	8,835	9,380	44,791	41,695		36,065
Amortization of completed technology	2,848	2,299	2,213	2,216	2,580	2,108	2,074	2,081	2,135	2,184	2,037	2,037	9,576	8,843		8,393
Total cost of revenue	15,490	11,961	12,793	14,123	14,541	11,947	12,091	11,959	11,636	10,533	10,872	11,417	54,367	50,538		44,458
Gross profit	30,985	28,916	26,243	28,015	29,653	28,552	26,303	27,480	28,126	25,718	22,854	23,183	114,159	111,988		99,881
Operating expenses:
Product development	8,758	8,622	9,729	10,368	9,892	9,658	9,747	9,552	8,779	8,261	8,402	8,535	37,477	38,849		33,977
Sales and marketing	16,925	13,372	15,356	15,133	17,528	12,765	13,813	13,865	14,173	11,516	12,339	13,489	60,786	57,971		51,517
General and administrative	4,366	3,655	4,098	4,384	4,229	4,358	4,367	4,526	4,047	4,079	3,960	4,381	16,503	17,480		16,467
Business consolidation, transaction and restructuring costs	1,479	9,776	2,063	2,159	6,588	606	(21)	630	1,550	2,205	2,418	1,602
Note Receivable Impairment	1,663	0	0	0									1,663	0		0
Purchased intangible asset amortization	3,051	2,415	2,411	2,433	2,619	2,107	2,118	2,095	2,503	2,555	2,394	2,394	10,310	8,939		9,846
Total operating expenses	36,242	37,840	33,657	34,477	40,856	29,494	30,024	30,668	31,052	28,616	29,513	30,401	142,216	131,042		119,582
Operating income (loss)	(5,257)	(8,924)	(7,414)	(6,462)	(11,203)	(942)	(3,721)	(3,188)	(2,926)	(2,898)	(6,659)	(7,218)	(28,057)	(19,054)		(19,701)
Net gain on sale of intellectual property	0	0	25,821	74									25,895	0		0
Net gain on sale of cost method investment									18,970	0	0	0	0	0		18,970
Royalty and other income, net	1,504	1,456	1,997	1,399	1,763	1,863	3,613	1,631	(3,259)	882	1,837	2,280	6,356	8,870		1,740
Income (loss) before income taxes	(3,753)	(7,468)	20,404	(4,989)	(9,440)	921	(108)	(1,557)	12,785	(2,016)	(4,822)	(4,938)	4,194	(10,184)		1,009
Income tax expense (benefit)	(3,677)	827	617	737	(1,211)	320	412	697	(1,420)	190	(33)	507	(1,496)	218	[1]	(756)
Net income (loss)	$ (76)	$ (8,295)	$ 19,787	$ (5,726)	$ (8,229)	$ 601	$ (520)	$ (2,254)	$ 14,205	$ (2,206)	$ (4,789)	$ (5,445)	$ 5,690	$ (10,402)		$ 1,765
Basic net income (loss) per share	$ (0.001)	$ (0.15)	$ 0.36	$ (0.10)	$ (0.15)	$ 0.01	$ (0.01)	$ (0.04)	$ 0.26	$ (0.04)	$ (0.09)	$ (0.10)	$ 0.10	$ (0.19)		$ 0.03
Diluted net income (loss) per share	$ (0.001)	$ (0.15)	$ 0.35	$ (0.10)	$ (0.15)	$ 0.01	$ (0.01)	$ (0.04)	$ 0.25	$ (0.04)	$ (0.09)	$ (0.10)	$ 0.10	$ (0.19)		$ 0.03

[1] Amounts for the years ended December 31, 2012 and December 31, 2011 have been recast to conform to current year presentation.