Note 9 - Revenues - Summary of Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Rental income	$ 5,875	$ 4,291	$ 14,629	$ 12,082
Sublease income		8		24
Total Out of Scope of Topic 606 revenue	5,875	4,299	14,629	12,106
Total revenues	7,007	5,232	17,623	14,541
Accounting Standards Update 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	1,132	933	2,994	2,435
Leasing Commissions [Member] | Accounting Standards Update 2014-09 [Member] | Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	668	534	1,734	1,349
Property and Asset Management Fees [Member] | Accounting Standards Update 2014-09 [Member] | Over Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	144	188	490	530
Development Fees [Member] | Accounting Standards Update 2014-09 [Member] | Over Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	70	92	247	273
Engineering Services [Member] | Accounting Standards Update 2014-09 [Member] | Over Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	64	83	197	224
Sales Commissions [Member] | Accounting Standards Update 2014-09 [Member] | Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue	$ 186	$ 36	$ 326	55
Equity Fees [Member] | Accounting Standards Update 2014-09 [Member] | Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Topic 606 Revenue				$ 4