CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
CONDENSED CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Revenues	$ 37,850	$ 35,906	$ 113,878	$ 106,136
Cost of revenues	17,372	16,097	52,156	46,793
Gross profit	20,478	19,809	61,722	59,343
Operating expenses:
Research and development	2,634	2,947	9,096	9,321
Sales and marketing	9,927	8,208	28,414	25,249
General and administrative	3,280	2,820	11,194	7,596
Total operating expenses	15,841	13,975	48,704	42,166
Income from operations	4,637	5,834	13,018	17,177
Interest and other income (expense), net	(91)	46	259	698
Income before income tax provision	4,546	5,880	13,277	17,875
Income tax provision	1,696	2,045	4,892	6,711
Net income	$ 2,850	$ 3,835	$ 8,385	$ 11,164
Net income per share:
Basic net income per share (in dollars per share)	$ 0.13	$ 0.17	$ 0.38	$ 0.50
Diluted net income per share (in dollars per share)	$ 0.13	$ 0.17	$ 0.37	$ 0.49
Shares used in the calculation of net income per share:
Weighted average common shares outstanding - basic (in shares)	21,672,000	22,398,000	22,213,000	22,309,000
Weighted average common shares outstanding - diluted (in shares)	21,990,000	22,872,000	22,579,000	22,795,000