CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Net sales and contract revenues:
Net product sales and contract revenues	$ 54,220	$ 75,982	$ 121,251
Net service revenues	48,767	50,768	68,998
Total net sales and contract revenues	102,987	126,750	190,249
Cost of sales and contracts:
Cost of product sales and contracts	31,826	44,084	76,952
Cost of service revenues	24,931	25,404	36,647
Total cost of sales and contracts	56,757	69,488	113,599
Gross profit	46,230	57,262	76,650
Operating expenses:
Selling, general and administrative expenses	29,838	32,707	31,805
Research and development expenses	21,722	23,390	22,089
Total operating expenses	51,560	56,097	53,894
Operating (loss) income	(5,330)	1,165	22,756
Other income (expense), net:
Interest and investment income, net	192	269	373
Interest expense		(18)	(53)
Other expense, net	(369)	(369)	(343)
Total other income (expense), net	(177)	(118)	(23)
(Loss) income before (benefit from) provision for income taxes	(5,507)	1,047	22,733
(Benefit from) provision for income taxes	(2,258)	68	7,616
Net (loss) income	(3,249)	979	15,117
Other comprehensive income (loss):
Unrealized gain (loss) on available for sale securities, net of tax	11	(24)	17
Comprehensive (loss) income	$ (3,238)	$ 955	$ 15,134
(Loss) income per share - Basic (in dollars per share)	$ (0.45)	$ 0.13	$ 1.92
(Loss) income per share - Diluted (in dollars per share)	$ (0.45)	$ 0.13	$ 1.91
Weighted average shares - Basic (in shares)	7,161	7,723	7,846
Weighted average shares - Diluted (in shares)	7,161	7,729	7,881
Dividends declared per share (in dollars per share)	$ 2.00	$ 2.00	$ 2.00