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	$ (2,170)	$ (4,978)	$ (6,189)
Adjustments to reconcile net loss to net cash provided by operating activities:
Allowance for sales returns, doubtful accounts and other	(3)	(8)	(5)
Provision for excess and obsolete inventories	1,172	1,067	2,079
Depreciation and amortization	1,459	1,633	1,981
Stock-based compensation	1,850	2,077	2,228
Deferred income taxes			1,224
Windfall tax benefits from stock options exercised			33
Amortization of bond premium on investment	209	593	842
Changes in assets and liabilities, net of impact of acquisition:
Accounts receivable	782	(11)	2,008
Inventory	66	(1,294)	3,545
Prepaid expenses and other assets	102	2,854	1,046
Accounts payable	(441)	(1,915)	1,066
Accrued expenses and other liabilities	(2,081)	811	(857)
Deferred revenue	(485)	292	(554)
Net cash provided by operating activities	460	1,121	8,447
Cash flows from investing activities:
Purchase of investments	(14,149)	(16,009)	(35,866)
Sales and maturities of investments	23,585	39,699	28,412
Acquisition	(4,359)
Restricted cash	(2,984)
Purchases of property and equipment	(1,158)	(481)	(761)
Net cash provided by (used in) investing activities	935	23,209	(8,215)
Cash flows from financing activities:
Repurchase of common stock	(7,026)	(30,026)	(2,880)
Windfall tax benefits from stock options exercised			(33)
Proceeds from issuance of common stock under employee stock plans	818	952	3,081
Net cash provided by (used in) financing activities	(6,208)	(29,074)	168
Net increase (decrease) in cash and cash equivalents	(4,813)	(4,744)	400
Cash and cash equivalents at beginning of the year	36,776	41,520	41,120
Cash and cash equivalents at end of the period	31,963	36,776	41,520
Non-cash financing activities:
Purchases of property and equipment through accounts payable and accruals		6
Supplemental cash flow information:
Net cash paid (received) for income taxes	$ 78	$ (2,394)	$ 2