Note 12 - Segments - Assets by Reportable Segment (Details) - USD ($)		Sep. 30, 2020	Dec. 31, 2019
Total assets		$ 191,817,949	$ 220,784,408
Cash, cash equivalents and restricted cash		10,006,026	10,391,275
Other assets, net		3,715,172	5,709,586
Operating Segments [Member]
Total assets		174,822,456	209,158,266
Segment Reconciling Items [Member]
Total assets		191,817,949	220,784,408
Cash, cash equivalents and restricted cash		1,913,279	1,591,041
Other assets, net		15,082,214	10,035,101
Office/Industrial Properties [Member] | Operating Segments [Member]
Land, buildings and improvements, net	[1]	102,805,132	126,421,648
Total assets	[2]	103,137,364	131,180,612
Model Home Properties [Member] | Operating Segments [Member]
Land, buildings and improvements, net	[1]	45,945,657	48,466,371
Total assets	[2]	45,235,619	51,389,400
Retail Properties [Member] | Operating Segments [Member]
Land, buildings and improvements, net	[1]	25,125,813	25,318,601
Total assets	[2]	$ 26,449,473	$ 26,588,254

[1] Includes lease intangibles and the land purchase option related to property acquisitions.

[2] Includes land, buildings and improvements, cash, cash equivalents, and restricted cash, current receivables, deferred rent receivables and deferred leasing costs and other related intangible assets, all shown on a net basis.