Note 9 - Employee Benefits (Details Textual)	3 Months Ended		12 Months Ended
	Apr. 29, 2017 USD ($) $ / shares shares	Apr. 30, 2016 USD ($)	Mar. 31, 2018 CNY (¥)	Mar. 31, 2017 CNY (¥)
Purchase Plan 2010 [Member]
Share Issued Under Employee Stock Purchase Plan, Subject to Rescission Rights | shares	40,582
Share Price | $ / shares	$ 3.89
General and Administrative Expense [Member] | Fiscal 2018 Plan [Member]
Restructuring Charges	$ 400,000
General and Administrative Expense [Member] | Fiscal 2018 Plan [Member] | One-time Termination Benefits [Member]
Restructuring Charges	200,000
Severance Plan [Member]
Defined Contribution Plan, Employer Contribution Related to Severances, Amount	100,000	$ 100,000
Supplemental Unemployment Benefits, Severance Benefits	900,000
Severance Employee Funds	$ 800,000
Domestic Plan [Member] | Endowment Insurance Pension Plan [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	8.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	20.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount | ¥				¥ 17,817
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 600,000	600,000
Domestic Plan [Member] | Endowment Insurance Pension Plan [Member] | Scenario, Forecast [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount | ¥			¥ 19,512
Denmark, Taiwan, The Netherlands and Germany [Member] | Retirement Pension Plan [Member]
Defined Contribution Plan, Cost		200,000
Defined Contribution Plan, Employer Discretionary Contribution Amount	200,000
Pension Plan [Member] | Domestic Plan [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount	18,000
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Additional Amount for Employees Over Age 50	6,000
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 200,000	$ 200,000