Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Inventory, accruals and reserves	$ 4,016	$ 3,686
Other	54	187
Deferred revenue	(141)	73
Valuation allowance	(3,929)	(3,946)
Total net current deferred tax assets and liabilities	0	0
Federal and state operating loss carry-forwards	23,927	19,727
Tax credit carry-forwards	1,403	1,475
Non-qualified stock options	3,265	3,125
Deferred revenue	(51)	(31)
Fixed assets	(1,360)	(1,493)
Intangible assets	(1,034)	(1,297)
Valuation allowance	(26,150)	(21,506)
Total net long-term deferred tax assets and liabilities	0	0
Total net deferred tax assets	$ 0	$ 0