Note 11 - Employee and Non-employee Stock Options (Details Textual) - Employee and Non Employee Director Options [Member] - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	1,682
Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price	$ 10.56
Allocated Share-based Compensation Expense, Total	$ 0	$ 0	$ 0	$ 0
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	$ 0		$ 0
Delphax [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	0	0	0	0