Note 8 - Revenues - Summary of Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation Of Revenue [Line Items]
Rental income	$ 3,938	$ 4,146
Sublease income		8
Total Out of Scope of Topic 606 revenue	3,938	4,154
Total revenues	4,918	5,124
Accounting Standards Update 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	980	970
Leasing Commissions [Member] | Accounting Standards Update 2014-09 [Member] | Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	589	591
Property and Asset Management Fees [Member] | Accounting Standards Update 2014-09 [Member] | Over Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	197	191
Development Fees [Member] | Accounting Standards Update 2014-09 [Member] | Over Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	89	93
Engineering Services [Member] | Accounting Standards Update 2014-09 [Member] | Over Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	59	76
Sales Commissions [Member] | Accounting Standards Update 2014-09 [Member] | Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	$ 46	$ 19