Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Condensed Consolidated Statements of Operations [Abstract]
Product revenue	$ 18,718	$ 15,086	$ 40,397	$ 30,844
Service revenue	542	767	1,637	1,986
Total revenue	19,260	15,853	42,034	32,830
Cost of product revenue	12,059	9,745	27,063	20,053
Cost of service revenue	382	498	1,116	1,415
Total cost of revenue	12,441	10,243	28,179	21,468
Gross profit	6,819	5,610	13,855	11,362
Operating expenses:
General and administrative	2,724	2,988	5,800	5,933
Sales and marketing	3,736	3,299	7,504	6,889
Research and development	593	573	1,215	1,183
Total operating expenses	7,053	6,860	14,519	14,005
Loss from operations	(234)	(1,250)	(664)	(2,643)
Other income (expense):
Interest expense	(150)	(55)	(237)	(124)
Dividend and interest income	214	153	368	246
Total other income	64	98	131	122
Loss before income tax	(170)	(1,152)	(533)	(2,521)
Income tax benefit	(71)	(1,692)	(215)	(2,525)
Net income (loss)	$ (99)	$ 540	$ (318)	$ 4
Basic net income (loss) per share attributable to common shareholders	$ 0	$ 0.02	$ (0.01)	$ 0
Weighted-average common shares outstanding	22,989,502	22,638,638	22,955,655	22,581,188
Diluted net income (loss) per share attributable to common shareholders	$ 0	$ 0.02	$ (0.01)	$ 0
Weighted-average common shares outstanding	22,989,502	22,901,590	22,955,655	23,007,067