CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net sales and contract revenues:
Net product sales and contract revenues	$ 11,004	$ 22,208	$ 34,255	$ 43,488
Net service revenues	12,062	21,608	24,348	43,412
Total net sales and contract revenues	23,066	43,816	58,603	86,900
Cost of sales and contracts:
Cost of product sales and contracts	6,531	14,341	18,829	26,894
Cost of service revenues	6,852	10,269	13,622	21,653
Total cost of sales and contracts	13,383	24,610	32,451	48,547
Gross profit	9,683	19,206	26,152	38,353
Expenses:
Selling, general and administrative expenses	9,118	6,913	17,309	14,322
Research and development costs	6,418	5,172	12,424	9,586
Total operating expenses	15,536	12,085	29,733	23,908
Operating income (loss)	(5,853)	7,121	(3,581)	14,445
Other income (expense):
Interest and investment income	87	75	165	169
Interest expense	(9)	(14)	(19)	(29)
Other, net	(99)	(56)	(252)	(143)
Total other income (expense)	(21)	5	(106)	(3)
Income (loss) before provision for (benefit from) income taxes	(5,874)	7,126	(3,687)	14,442
Provision for (benefit from) income taxes	(1,968)	2,387	(1,235)	4,838
Net income (loss)	(3,906)	4,739	(2,452)	9,604
Other comprehensive income (loss):
Unrealized gain (loss) on available for sale securities (net of tax)	(15)	60	(29)	34
Comprehensive income (loss)	$ (3,921)	$ 4,799	$ (2,481)	$ 9,638
Income (loss) per share - Basic (in dollars per share)	$ (0.49)	$ 0.61	$ (0.31)	$ 1.23
Income (loss) per share - Diluted (in dollars per share)	$ (0.49)	$ 0.60	$ (0.31)	$ 1.22
Weighted average shares - Basic (in shares)	7,917	7,820	7,904	7,831
Weighted average shares - Diluted (in shares)	7,917	7,851	7,904	7,866
Dividends declared per share (in dollars per share)	$ 0.50	$ 0.50	$ 1.00	$ 1.00