Selected Quarterly Financial Data (Unaudited) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Summary of selected unaudited financial data
Revenue	$ 49,906	$ 53,164	$ 52,448	$ 47,919	$ 57,532	$ 55,658	$ 57,159	$ 49,192	$ 203,437	$ 219,541	$ 214,386
Cost of revenue	9,361	9,101	8,994	8,956	8,837	9,239	9,201	12,122	36,412	39,399	64,771
Gross profit	40,545	44,063	43,454	38,963	48,695	46,419	47,958	37,070	167,025	180,142	149,615
Operating expenses	32,072	34,763	36,094	35,297	35,530	35,469	36,498	34,478	138,226	141,975	146,703
Operating income	8,473	9,300	7,360	3,666	13,165	10,950	11,460	2,592	28,799	38,167	2,912
Income (loss) before income taxes	768	2,007	(246)	(4,027)	6,464	4,154	4,656	(5,412)	(1,498)	9,862	(21,704)
Income tax (benefit) provision	(1,008)	(2,127)	68	(914)	426	952	57	(5,412)	(3,981)	918	(12,437)
Net income (loss)	$ 1,776	$ 4,134	$ (314)	$ (3,113)	$ 6,038	$ 3,202	$ 4,599	$ (4,895)	$ 2,483	$ 8,944	$ (9,267)