Note F - Investment in and Transactions with Unconsolidated Subsidiaries (Details Textual)	1 Months Ended		5 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($)	Jun. 30, 2014 USD ($)	Nov. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Accounts Receivable, Allowance for Credit Loss, Ending Balance	$ 10,000			$ 10,000	$ 10,000
Income (Loss) from Equity Method Investments, Total				81,324	329,700
Milestone China [Member]
Equity Method Investments	0	$ 1,000,000		0	0
Long-term Purchase Commitment, Minimum Quantity Required		772
Equity Method Investment, Ownership Percentage		40.00%
Financing Receivable, after Allowance for Credit Loss, Total	2,800,000				2,800,000
Account Receivables, Related Party, Monthly Payment			$ 200,000
Accounts Receivable, Related Party, Balloon Payment to be Paid	1,425,000
Proceeds from Collection of Finance Receivables					950,000
Contract With Customer Liability Before Reserve Adjustment	1,800,000				1,800,000
Capitalized Contract Before Reserve Adjustment	1,250,000				1,250,000
Accounts Receivable, Allowance for Credit Loss, Ending Balance	1,250,000				1,250,000
Contract with Customer, Liability, Total	100,000			259,000	100,000
Capitalized Contract Cost, Net, Total	50,000			104,000	50,000
Revenue from Related Parties					$ 900,000
Contract with Customer, Liability, Revenue Recognized				0
Equity Method Investment, Deferred Intercompany Profit (Loss), Percentage					40.00%
Income (Loss) from Equity Method Investments, Total				81,324	$ (329,700)
Cost-method Investments, Realized Losses				4,308,596	3,380,388
Milestone China [Member] | Accounts Receivable from Related Parties [Member]
Equity Method Investment, Deferred Intercompany Profit (Loss)	$ 421,800			$ 340,476	$ 421,800