CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net sales and contract revenues:
Net product sales and contract revenues	$ 13,425	$ 11,004	$ 32,566	$ 34,255
Net service revenues	11,712	12,062	24,015	24,348
Total net sales and contract revenues	25,137	23,066	56,581	58,603
Cost of sales and contracts:
Cost of product sales and contracts	7,045	6,531	17,665	18,829
Cost of service revenues	5,738	6,852	12,136	13,622
Total cost of sales and contracts	12,783	13,383	29,801	32,451
Gross profit	12,354	9,683	26,780	26,152
Expenses:
Selling, general and administrative expenses	6,772	9,118	15,042	17,309
Research and development costs	4,751	6,418	11,640	12,424
Total operating expenses	11,523	15,536	26,682	29,733
Operating income (loss)	831	(5,853)	98	(3,581)
Other income (expense):
Interest and investment income	55	87	89	165
Interest expense		(9)		(19)
Other, net	(172)	(99)	(265)	(252)
Total other expense	(117)	(21)	(176)	(106)
Income (loss) before provision for (benefit from) income taxes	714	(5,874)	(78)	(3,687)
Provision for (benefit from) income taxes	250	(1,968)	(27)	(1,235)
Net income (loss)	464	(3,906)	(51)	(2,452)
Other comprehensive income (loss):
Unrealized gain (loss) on available for sale securities (net of tax)	3	(15)	4	(29)
Comprehensive income (loss)	$ 467	$ (3,921)	$ (47)	$ (2,481)
Income (loss) per share - Basic (in dollars per share)	$ 0.06	$ (0.49)	$ (0.01)	$ (0.31)
Income (loss) per share - Diluted (in dollars per share)	$ 0.06	$ (0.49)	$ (0.01)	$ (0.31)
Weighted average shares - Basic (in shares)	7,151	7,917	7,156	7,904
Weighted average shares - Diluted (in shares)	7,156	7,917	7,156	7,904
Dividends declared per share (in dollars per share)	$ 0.50	$ 0.50	$ 1.00	$ 1.00