Note 1 - Description of Business and Summary of Significant Accounting Policies (Details Textual) $ / shares in Units, $ in Thousands				3 Months Ended								12 Months Ended
	May 13, 2020 USD ($)	Apr. 30, 2020 USD ($)	Jul. 31, 2018 USD ($) $ / shares	Dec. 31, 2020 USD ($) $ / shares	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) $ / shares	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares
Number of Reportable Segments												3
Cash and Cash Equivalents, at Carrying Value, Ending Balance				$ 3,372				$ 2,416				$ 3,372	$ 2,416
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total												956	$ 1,239
Debt and Lease Obligation, Total				14,210								14,210
Debt, Current, Total				$ 2,833								$ 2,833
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			$ 0.001	$ 0.001				$ 0.001				$ 0.001	$ 0.001
Proceeds from Issuance of Common Stock, Net												$ 232
Interest Income, Other												0	0
Revenue from Contract with Customer, Including Assessed Tax				$ 40,322	$ 54,614	$ 54,926	$ 48,634	$ 49,253	$ 46,138	$ 41,169	$ 41,660	198,496	178,220
Depreciation, Total												$ 5,546	$ 5,814
Accounts Receivable [Member] | Customer Concentration Risk [Member]
Number of Major Customers												5	5
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Five Largest Customers [Member]
Concentration Risk, Percentage												65.00%	55.00%
Revenue from Contract with Customer Benchmark [Member] | Customer Concentration Risk [Member]
Number of Major Customers												5	5
Revenue from Contract with Customer Benchmark [Member] | Customer Concentration Risk [Member] | Five Largest Customers [Member]
Concentration Risk, Percentage												78.00%	79.00%
Transferred over Time [Member]
Revenue from Contract with Customer, Including Assessed Tax												$ 2,253	$ 0
Paycheck Protection Program CARES Act [Member]
Proceeds from Issuance of Unsecured Debt		$ 9,530
Repayments of Unsecured Debt	$ 379
The ATM Agreement [Member]
Value of Shares Issuable, Maximum			$ 10,000
Sales Agent Commission Percentage			3.00%
Stock Issued During Period, Shares, New Issues (in shares) | shares												91,481	0
Proceeds from Issuance of Common Stock, Net												$ 321
Payments of Stock Issuance Costs												10
Other Stock Issuance Expenses												89
Revolving Credit Facility [Member]
Line of Credit Facility, Remaining Borrowing Capacity				20,678								20,678
Line of Credit, Current				$ 1,245								$ 1,245
Maximum [Member]
Product Warranty Term (Year)												5 years
Minimum [Member]
Product Warranty Term (Year)												1 year
Heavy Fabrications [Member]
Number of Facilities												2
Number of Tower Sections in Production Capacity of Turbines Total												1,650
Heavy Fabrications [Member] | Customer Concentration Risk [Member]
Number of Major Customers												1	1
Heavy Fabrications [Member] | Maximum [Member]
Annual Tower Production Capacity												550
Heavy Fabrications [Member] | Minimum [Member]
Power Generating Capacity of Turbines												1,100