CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net loss	$ (1,446)	$ (441)
Adjustments to reconcile loss to net cash provided by operating activities:
Allowance for sales returns, doubtful accounts and other	(11)	(16)
Provision for excess and obsolete inventories	356	507
Depreciation and amortization	510	494
Stock-based compensation.	573	565
Deferred income taxes		126
Windfall tax benefits from stock options exercised	0	(177)
Amortization of bond premium on investments	187	220
Changes in assets and liabilities:
Accounts receivable	(709)	(27)
Inventory	(534)	1,125
Prepaid expenses and other assets	249	282
Accounts payable	(1,243)	(346)
Accrued expenses and other liabilities	(966)	98
Deferred revenue	1,135	(488)
Net cash provided by (used in) operating activities	(1,899)	1,922
Cash flows from investing activities:
Purchase of investments	(250)	(11,584)
Sales and maturities of short-term investments	4,596	10,383
Purchases of property and equipment	(24)	(34)
Net cash provided by (used in) investing activities	4,322	(1,235)
Cash flows from financing activities:
Repurchase of common stock	(913)
Windfall tax benefits from stock options exercised		177
Proceeds from issuance of common stock under employee stock plans	316	797
Net cash provided by (used in) financing activities	(597)	974
Net increase in cash and cash equivalents	1,826	1,661
Cash and cash equivalents at beginning of the year	41,520	41,120
Cash and cash equivalents at end of the period	43,346	42,781
Non-cash financing activities:
Purchases of property and equipment through accounts payable and accruals		17
Supplemental cash flow information:
Net cash paid for income taxes	$ 31