Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual)		3 Months Ended		6 Months Ended		12 Months Ended
	May 08, 2020 $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) shares	Dec. 31, 2019 USD ($) $ / shares	Jun. 28, 2019 USD ($)
Entity Public Float							$ 58,900,000
Restricted Cash, Total		$ 144,000	$ 124,000	$ 144,000	$ 124,000	$ 117,000
Impairment of Real Estate		19,000,000.0	0	19,000,000.0	0
Abandoned Project Costs		100,000	14,000	14,130,000	$ 19,000
Nonrefundable Cash Deposits		12,600,000		12,600,000
Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance		$ 112,000		$ 112,000		112,000
Capitalized Contract Cost, Amortization Period (Month)		30 months		30 months
Period of General Warranty (Year)				1 year
Accounts Receivable, Allowance for Credit Loss, Ending Balance		$ 0		$ 0		0
Capitalized Selling and Marketing Cost, Amortization Period (Month)				30 months
Deferred Tax Assets, Valuation Allowance, Total		140,000		$ 140,000		$ 0
Unrecognized Tax Benefits, Ending Balance		0		0
Income Tax Examination, Penalties and Interest Accrued, Total		$ 0		$ 0
Stock Repurchased and Retired During Period, Shares (in shares) | shares		817,300		2,051,183	153,916
Stock Repurchased and Retired During Period, Value		$ 1,485,000		$ 3,718,000	$ 1,042,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 1,700,000		$ 1,700,000
Dividend, Declared, Preferred Stock Purchase Right Per Common Share (in shares) | shares	1
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares	$ 0.01	$ 0.01		$ 0.01		$ 0.01
Preferred Stock Purchase Right, Exercise Price (in dollars per share) | $ / shares	$ 11.50
Dividends, Common Stock, Total		$ 0	0	$ 0	0
Unconsolidated Joint Ventures [Member]
Equity Method Investment, Other than Temporary Impairment		$ 20,000,000.0	$ 0	$ 22,300,000	0
Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)				5 years
Maximum [Member] | Unconsolidated Joint Ventures [Member]
Equity Method Investment, Ownership Percentage		35.00%		35.00%		35.00%
Minimum [Member]
Limited Warranty Period (Year)				2 years
Property, Plant and Equipment, Useful Life (Year)				3 years
Minimum [Member] | Unconsolidated Joint Ventures [Member]
Equity Method Investment, Ownership Percentage		5.00%		5.00%		5.00%
Noncontrolling Interest [Member]
Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance		$ 100,000		$ 100,000		$ 100,000
Stock Repurchased and Retired During Period, Value		$ (0)		$ (0)	$ (0)
Customer Concentration Risk [Member] | Fee Building Revenue [Member]
Number of Major Customers		1	1	1	1
Customer Concentration Risk [Member] | Fee Building Revenue [Member] | One Customer [Member]
Concentration Risk, Percentage		94.00%	95.00%	97.00%	93.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Number of Major Customers				1		1
Customer Concentration Risk [Member] | Accounts Receivable [Member] | One Customer [Member]
Concentration Risk, Percentage				51.00%		65.00%