Consolidated Statements of Shareholders' Equity (USD $)	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital Common Stock [Member]	Additional Paid-in Capital Warrants [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings (Accumulated Deficit) [Member]	Total
Balance at Mar. 31, 2012	$ 125,000	$ (89,000)	$ 98,627,000	$ 1,879,000	$ (884,000)	$ (26,039,000)	$ 73,619,000
Balance (in shares) at Mar. 31, 2012	12,533,821	(14,400)
Compensation recognized under employee stock plans	0	0	752,000	0	0	0	752,000
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)	52,530
Common stock issued under stock plans, net of shares withheld for employee taxes	1,000		241,000				242,000
Repurchase of options granted			(455,000)				(455,000)
Tax benefit from employee stock options exercised	0	0	101,000	0	0	0	101,000
Expired unexercised warrants			1,879,000	(1,879,000)			0
Repurchase of common stock including fees (in shares)		(52,947)
Repurchase of common stock including fees		(300,000)					(300,000)
Cancellation of treasury stock (in shares)	(67,347)	67,347
Cancellation of treasury stock	(1,000)	389,000	(388,000)				0
Common stock issued in connection with PIPE (in shares)	1,936,000	0
Common stock issued in connection with PIPE	20,000	0	14,985,000	0	0	0	15,005,000
Stock issuance costs	0	0	(1,034,000)	0			(1,034,000)
Common stock issued in lieu of cash for PIPE liquidated damages (in shares)	5,975	0
Common stock issued in lieu of cash for PIPE liquidated damages	0	0	29,000				29,000
Unrealized gain on investments, net of tax	0	0	0	0	162,000	0	162,000
Foreign currency translation	0	0	0	0	(124,000)	0	(124,000)
Net income (loss)	0	0	0	0	0	(91,511,000)	(91,511,000)
Balance at Mar. 31, 2013	145,000	0	114,737,000	0	(846,000)	(117,550,000)	(3,514,000)
Balance (in shares) at Mar. 31, 2013	14,460,979	0
Compensation recognized under employee stock plans	0	0	969,000	0	0	0	969,000
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)	606,666
Common stock issued under stock plans, net of shares withheld for employee taxes	6,000		5,760,000				5,766,000
Repurchase of options granted			(627,000)				(627,000)
Tax benefit from employee stock options exercised	0	0	(286,000)	0	0	0	(286,000)
Unrealized gain on investments, net of tax	0	0	0	0	34,000	0	34,000
Foreign currency translation	0	0	0	0	(65,000)	0	(65,000)
Net income (loss)	0	0	0	0	0	107,359,000	107,359,000
Balance at Mar. 31, 2014	151,000	0	120,553,000	0	(877,000)	(10,191,000)	109,636,000
Balance (in shares) at Mar. 31, 2014	15,067,645	0
Compensation recognized under employee stock plans	0	0	2,210,000	0	0	0	2,210,000
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)	123,734
Common stock issued under stock plans, net of shares withheld for employee taxes	1,000		1,246,000				1,247,000
Issuance of common stock upon vesting of RSU's, net of shares withheld for employee taxes (in shares)	23,219
Issuance of common stock upon vesting of RSU's, net of shares withheld for employee taxes	0		(806,000)				(806,000)
Tax benefit from employee stock options exercised	0	0	1,131,000	0	0	0	1,131,000
Common stock issued in connection with public offering (in shares)	2,760,000	0
Common stock issued in connection with public offering	28,000	0	71,732,000	0	0	0	71,760,000
Stock issuance costs	0	0	(4,787,000)	0			(4,787,000)
Unrealized gain on investments, net of tax	0	0	0	0	24,000	0	24,000
Foreign currency translation	0	0	0	0	(1,665,000)	0	(1,665,000)
Net income (loss)	0	0	0	0	0	11,453,000	11,453,000
Balance at Mar. 31, 2015	$ 180,000	$ 0	$ 191,279,000	$ 0	$ (2,518,000)	$ 1,262,000	$ 190,203,000
Balance (in shares) at Mar. 31, 2015	17,974,598	0