Note 3 - Restructuring and Other Charges (Details Textual) - USD ($) $ in Thousands		3 Months Ended						6 Months Ended	12 Months Ended
	Dec. 28, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Lease, Impairment Loss		$ 612							$ 612
Operating Lease, Right-of-Use Asset		6,387							6,387	4,842
Restructuring Charges, Total		1,078	$ 161	$ 38	$ 8	$ 17	$ 223
Lease Agreement, EMS Facility in Mt. Laurel, New Jersey [Member]
Operating Lease, Right-of-Use Asset		139							139
Severance and Other One-Time Termination Benefits [Member]
Restructuring Charges, Total									248	137
EMS Segment Restructuring and Facility Consolidation [Member]
Restructuring and Related Costs, Incurred Cost, Total									903
Operating Lease, Impairment Loss	$ 522								522
Operating Lease, Right-of-Use Asset		597							597
Other Restructuring Costs									159
EMS Segment Restructuring and Facility Consolidation [Member] | Minimum [Member] | Forecast [Member]
Restructuring and Related Costs, Incurred Cost, Total								$ 100
EMS Segment Restructuring and Facility Consolidation [Member] | Maximum [Member] | Forecast [Member]
Restructuring and Related Costs, Incurred Cost, Total								$ 150
Executive Management Changes [Member]
Operating Lease, Impairment Loss		$ 90							90
Restructuring Charges, Total									514
Share-based Payment Arrangement, Reversal of Expense									117
Other Restructuring Costs									381
Executive Management Changes [Member] | Facility Size Reduction [Member]
Other Restructuring Costs									99
Other Restructuring Actions [Member] | Headcount Reductions and Employee Relocation [Member]
Other Restructuring Costs									46
Other Restructuring Actions [Member] | Employee Relocation [Member]
Other Restructuring Costs									$ 14
Ambrell European Operations Consolidation [Member]
Restructuring Charges, Total										240
Ambrell European Operations Consolidation [Member] | Severance and Other One-Time Termination Benefits [Member]
Restructuring Charges, Total										137
Ambrell European Operations Consolidation [Member] | Facility Closing [Member]
Restructuring Charges, Total										$ 103