Note 12 - Earnings (Loss) Per Share - Summary of Reconciliations Between the Numerator and the Denominator of the Basic and Diluted Earnings Per Share Computations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Net income (loss)	$ 121	$ 171	$ 228	$ (133)	$ (1,473)	$ 288	$ (1,136)	$ (1,275)	$ 387	$ (3,596)	$ 1,025
Shares outstanding - basic (in shares)									5,956	5,819	5,709
Earnings per share - basic (in dollars per share)									$ 0.06	$ (0.62)	$ 0.18
Effective dilutive securities—Common stock options
Effective dilutive securities—Common stock options oustanding (in shares)									5		72
Net income - diluted									$ 387		$ 1,025
Shares outstanding - diluted (in shares)									5,961	5,819	5,781
Earnings per share - diluted (in dollars per share)									$ 0.06	$ (0.62)	$ 0.18
Basic and diluted loss per share (in shares)										5,819
Basic and diluted loss per share (in dollars per share)	$ 0.01	$ 0.03	$ 0.04	$ (0.02)	$ (0.25)	$ 0.05	$ (0.20)	$ (0.22)	$ 0.06	$ (0.62)