CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) [Abstract]
Revenues	$ 55,975	$ 50,471	$ 109,065	$ 94,525
Cost of revenues	24,013	22,395	47,711	42,746
Gross profit	31,962	28,076	61,354	51,779
Operating expenses:
Research and development	4,689	4,232	9,412	8,179
Sales and marketing	10,785	10,619	21,371	19,451
General and administrative	4,319	3,797	7,777	6,705
Total operating expenses	19,793	18,648	38,560	34,335
Income from operations	12,169	9,428	22,794	17,444
Interest and other income (expense), net	126	(445)	485	(398)
Income from continuing operations before income tax provision	12,295	8,983	23,279	17,046
Income tax provision	4,472	3,271	8,461	6,260
Income from continuing operations	7,823	5,712	14,818	10,786
Discontinued operations (Note 4)
Loss from discontinued operations, net of tax	(7)	(312)	(7)	(671)
Net income	$ 7,816	$ 5,400	$ 14,811	$ 10,115
Basic
Continuing operations (in dollars per share)	$ 0.34	$ 0.25	$ 0.65	$ 0.48
Discontinued operations (in dollars per share)	0	(0.01)	0	(0.03)
Basic net income per share (in dollars per share)	0.34	0.24	0.65	0.45
Diluted
Continuing operations (in dollars per share)	0.34	0.25	0.65	0.48
Discontinued operations (in dollars per share)	0	(0.01)	0	(0.03)
Diluted net income per share (in dollars per share)	$ 0.34	$ 0.24	$ 0.65	$ 0.45
Shares used in the calculation of net income per share:
Weighted average common shares outstanding - basic (in shares)	22,701,000	22,507,000	22,663,000	22,458,000
Weighted average common shares outstanding - diluted (in shares)	22,863,000	22,690,000	22,876,000	22,678,000
Cash dividends declared per share (in dollars per share)	$ 0.11	$ 0.10	$ 0.22	$ 0.20