Note 11 - Computation of Basic and Diluted Net Loss Per Share - Antidilutive Securities Excluded From the Computation of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Antidilutive securities (in shares)	5,969	6,475	5,945	4,555
Employee Stock Option [Member]
Antidilutive securities (in shares)	4,101	4,176	4,101	2,241
Restricted Stock Units (RSUs) [Member]
Antidilutive securities (in shares)	120	37	96	52
Warrant [Member]
Antidilutive securities (in shares)	1,748	2,262	1,748	2,262