Leases - Lease assets and liabilities (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Current
Prepaid expenses and other current assets	$ 93,323	$ 108,303
Current assets of discontinued operations	26,197
Noncurrent
Operating lease right-of-use assets	2,889,508	1,329,561
Long-term assets of discontinued operations		33,909
Total lease right-of-use assets	3,009,028	1,471,773
Current
Current maturities of operating leases	462,464	455,788
Current liabilities of discontinued operations	24,669	29,432
Noncurrent
Noncurrent operating leases	2,520,367	982,076
Noncurrent liabilities of discontinued operations	0	2,499
Total lease obligations	$ 3,007,500	$ 1,469,795
Operating leases, weighted average remaining lease term	7 years 6 months	3 years 4 months 24 days
Operating leases, weighted average discount rate	4.92%	4.15%
Discontinued Operations
Noncurrent
Operating leases, weighted average remaining lease term	10 months 24 days	1 year 1 month 6 days
Operating leases, weighted average discount rate	3.48%	3.48%