Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2021	Mar. 31, 2021
Allowance for doubtful accounts	$ 28	$ 39
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000	5,000
Preferred stock, liquidation preference (in dollars per share)	$ 4	$ 4
Preferred stock, shares issued (in shares)	3	3
Preferred stock, shares outstanding (in shares)	3	3
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	40,000	40,000
Common stock, shares issued (in shares)	20,943	20,269
Common stock, shares outstanding (in shares)	20,943	20,269