Note 3 - Discontinued Operations and Sale of a Business - Schedule of Discontinued Operations for Income Statement and Balance Sheet Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Assets held for sale, current portion	$ 6,611		$ 6,679
Liabilities held for sale, current portion	5,735		4,367
Liabilities held for sale, noncurrent portion	1,753		0
Total income from discontinued operations	(953)	$ (1,643)
Discontinued Operations, Held-for-sale [Member]
Trade accounts receivable	3,109		2,996
Revenues	3,986	3,930
Cost of revenues	(2,694)	(2,715)
Selling, general and administrative expense	(2,139)	(2,443)
Depreciation and amortization	0	(432)
(Provision) credit for bad debt	(91)	19
Interest expense	(7)	(2)
Other expense	(8)	0
Pretax income of discontinued operations	(953)	(1,643)
Income tax expense	0	0
Total income from discontinued operations	(953)	$ (1,643)
Discontinued Operations, Held-for-sale [Member] | Orbital Gas Systems Limited [Member]
Inventories	547
Prepaid expenses and other current assets	212
Contract assets	835
Assets held for sale, current portion	4,703
Property and equipment	52
Other intangible assets	1,813
Deposits and other assets	43
Assets held for sale, noncurrent portion	1,908
Total assets of the disposal group classified as held for sale	6,611
Accounts payable	1,564
Contract liabilities	2,537
Operating lease obligations - current portion	73
Accrued expenses	1,474
Liabilities held for sale, current portion	5,648
Operating lease obligations, less current portion	82
Other long-term liabilities	5
Liabilities held for sale, noncurrent portion	87
Total liabilities held for sale	$ 5,735
Discontinued Operations, Held-for-sale [Member] | Power and Electromechanical Business [Member]
Inventories			530
Prepaid expenses and other current assets			114
Contract assets			1,141
Assets held for sale, current portion			4,781
Property and equipment			42
Other intangible assets			1,813
Deposits and other assets			43
Assets held for sale, noncurrent portion			1,898
Total assets of the disposal group classified as held for sale			6,679
Accounts payable			1,657
Contract liabilities			1,414
Operating lease obligations - current portion			76
Accrued expenses			1,126
Liabilities held for sale, current portion			4,273
Operating lease obligations, less current portion			85
Other long-term liabilities			9
Liabilities held for sale, noncurrent portion			94
Total liabilities held for sale			$ 4,367