Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Mar. 31, 2015	$ 79,893	$ 96	$ 985,921	$ (771)	$ (308)	$ (905,045)
Balance (in shares) at Mar. 31, 2015		9,624
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock - ESPP	30		30
Issuance of common stock - ESPP (in shares)		8
Issuance of common stock - restricted shares	0	$ 4	(4)
Issuance of common stock - restricted shares (in shares)		409
Stock-based compensation expense	3,248		3,248
Issuance of stock for 401(k) match	377	$ 1	376
Issuance of stock for 401(k) match (in shares)		66
Issuance of common stock-equity offering	22,282	$ 40	22,242
Issuance of common stock-equity offering (in shares)		4,000
Repurchase of treasury stock	(110)			(110)
Cumulative translation adjustment	968				968
Net loss	(23,139)					(23,139)
Balance at Mar. 31, 2016	83,549	$ 141	1,011,813	(881)	660	(928,184)
Balance (in shares) at Mar. 31, 2016		14,107
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock - restricted shares	0	$ 2	(2)
Issuance of common stock - restricted shares (in shares)		174
Stock-based compensation expense	2,892		2,892
Issuance of stock for 401(k) match	284		284
Issuance of stock for 401(k) match (in shares)		53
Issuance of common stock-equity offering	2,527	$ 4	2,523
Issuance of common stock-equity offering (in shares)		380
Repurchase of treasury stock	(490)			(490)
Cumulative translation adjustment	(1,163)				(1,163)
Net loss	(27,373)					(27,373)
Balance at Mar. 31, 2017	60,226	$ 147	1,017,510	(1,371)	(503)	(955,557)
Balance (in shares) at Mar. 31, 2017		14,714
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock - ESPP	174		174
Issuance of common stock - ESPP (in shares)		40
Issuance of common stock - restricted shares	0	$ 8	(8)
Issuance of common stock - restricted shares (in shares)		819
Stock-based compensation expense	2,692		2,692
Issuance of stock for 401(k) match	351	$ 1	350
Issuance of stock for 401(k) match (in shares)		81
Issuance of common stock-equity offering	16,952	$ 46	16,906
Issuance of common stock-equity offering (in shares)		4,600
Issuance of stock in business acquisition	3,498	$ 9	3,489
Issuance of stock in business acquisition (in shares)		885
Repurchase of treasury stock	(274)			(274)
Cumulative translation adjustment	1,386				1,386
Net loss	(32,776)					(32,776)
Balance at Mar. 31, 2018	$ 52,229	$ 211	$ 1,041,113	$ (1,645)	$ 883	$ (988,333)
Balance (in shares) at Mar. 31, 2018		21,139