Note 2 - Summary of Significant Accounting Policies (Details Textual)	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Revenue from Contract with Customer, Including Assessed Tax	$ 21,103,124	$ 22,244,681	$ 24,514,636	$ 21,836,087	$ 21,135,277	$ 19,771,137	$ 13,593,192	$ 11,878,700	$ 89,698,527	$ 66,378,306
Transferred over Time [Member]
Revenue from Contract with Customer, Including Assessed Tax									51,600,000	41,800,000
Transferred at Point in Time [Member]
Revenue from Contract with Customer, Including Assessed Tax									38,100,000	24,600,000
Commercial Air Handling [Member]
Revenue from Contract with Customer, Including Assessed Tax									51,564,344	41,833,444
Aerospace [Member]
Revenue from Contract with Customer, Including Assessed Tax									$ 30,126,438	$ 14,397,557
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Commercial Air Handling [Member]
Number of Customers									3
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Commercial Air Handling [Member] | Three Customers [Member]
Concentration Risk, Percentage									12.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Aerospace [Member]
Number of Customers									1	1
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Aerospace [Member] | One Customer [Member]
Concentration Risk, Percentage									29.00%	18.00%