CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net (loss) income	$ (3,249)	$ 979	$ 15,117
Adjustments to reconcile net (loss) income to net cash provided by (used for) operating activities:
Depreciation and amortization	3,619	4,565	5,303
Provisions for contracts, inventory and accounts receivable reserves	1,220	674	1,328
Amortization of bond premium	72	832	1,551
Stock compensation expense	1,607	2,771	2,501
(Gain) loss on disposal of fixed assets	213	(49)
Deferred income taxes	257	2,655	378
Changes in assets and liabilities:
Accounts receivable	2,566	12,183	(5,813)
Unbilled costs and fees	(402)	643	2,384
Inventories	1,795	(8,271)	13,761
Prepaid expenses and other assets	3,257	(5,237)	3,636
Accrued income taxes		(2,338)	244
Accounts payable	(1,873)	(3,418)	2,247
Deferred revenue	4,834	(6,501)	(6,430)
Customer deposits	(1,169)	(2,633)	390
Accrued expenses and other liabilities	(4,387)	(7,991)	(4,051)
Total adjustments	11,609	(12,115)	17,429
Net cash provided by (used for) operating activities	8,360	(11,136)	32,546
Cash flows from investing activities:
Proceeds from sales and maturities of short-term investments	24,472	92,471	88,040
Purchases of short-term investments		(29,211)	(69,668)
Purchases of equipment and leasehold improvements	(1,598)	(2,580)	(1,821)
Net cash provided by investing activities	22,874	60,680	16,551
Cash flows from financing activities:
(Increase) decrease in restricted cash	(845)	8,515	(1,399)
Repurchase of shares of common stock	(3,131)	(36,472)	(12,306)
Payment of common stock dividends	(14,453)	(15,607)	(15,713)
Repayment of leasehold financing		(653)	(1,488)
Proceeds from exercise of stock options		1,074	3,525
Tax benefit (expense) on share based compensation	(69)	291	9
Net cash used for financing activities	(18,498)	(42,852)	(27,372)
Net increase in cash and cash equivalents	12,736	6,692	21,725
Cash and cash equivalents at beginning of year	68,835	62,143	40,418
Cash and cash equivalents at end of year	81,571	68,835	62,143
Supplemental disclosures of cash flow information:
Write-off of asset and related leasehold financing liability (Note 2)		2,262
Interest paid		18	53
Income taxes paid	$ 205	$ 5,102	$ 8,723