Leases - Components of lease cost (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases
Operating lease costs	$ 242,277	$ 128,096	$ 486,169	$ 349,227
Short-term lease costs	1,402	4,078	5,518	8,035
Total lease costs	$ 243,679	$ 132,174	$ 491,687	$ 357,262