CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Operating activities
Net loss	$ (6,674)	$ (13,128)	$ (12,288)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	1,339	1,404	1,451
Amortization of intangible assets	444	607	881
Stock-based compensation	825	1,102	1,605
Amortization of debt issue costs	101	92	110
Impairment of intangible assets		710	250
Provision for inventory reserves	(202)	1,261	2,212
Provision for bad debts	56	22	132
Other	57	(94)	178
Changes in operating assets and liabilities:
Accounts receivable	(5,840)	419	1,687
Revenue earned but not billed	(1,390)
Inventories	(4,689)	4,706	1,220
Deferred contract costs	0	(65)	(899)
Prepaid expenses and other current assets	68	391	1,974
Accounts payable	8,916	20	(81)
Accrued expenses and other	1,975	(1,736)	(635)
Deferred revenue, current and long-term	(44)	(126)	300
Net cash used in operating activities	(5,058)	(4,415)	(1,903)
Investing activities
Purchase of property and equipment	(381)	(512)	(660)
Additions to patents and licenses	(68)	(73)	(291)
Proceeds from sales of property, plant and equipment			2,600
Net cash (used in) provided by investing activities	(449)	(585)	1,649
Financing activities
Payment of long-term debt	(80)	(158)	(880)
Proceeds from revolving credit facility	60,270	68,734	87,935
Payment of revolving credit facility	(54,976)	(71,456)	(85,025)
Payments to settle employee tax withholdings on stock-based compensation	(10)	(9)	(19)
Debt issue costs	(396)
Net proceeds from employee equity exercises	4	6	8
Net cash provided by (used in) financing activities	4,812	(2,883)	2,019
Net (decrease) increase in cash and cash equivalents	(695)	(7,883)	1,765
Cash and cash equivalents at beginning of period	9,424	17,307	15,542
Cash and cash equivalents at end of period	8,729	9,424	17,307
Supplemental cash flow information:
Cash paid for interest	(176)	(147)	(164)
Cash received for income taxes	12	$ 17	153
Supplemental disclosure of non-cash investing and financing activities:
Purchase of property, plant and equipment by issuing a debt	$ 74		$ 175