Note 7 - 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		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive securities (in shares)	6,501	6,597	4,413	6,597
Employee Stock Option [Member]
Antidilutive securities (in shares)	4,189	4,206	2,092	4,156
Restricted Stock Units (RSUs) [Member]
Antidilutive securities (in shares)	50	129	59	179
Warrant [Member]
Antidilutive securities (in shares)	2,262	2,262	2,262	2,262