Leases - Maturity of operating leases (Details)	Jun. 30, 2019 USD ($)
Net (liability) asset  position
Remainder of 2019	$ 917,930
2020	1,882,422
2021	1,962,242
2022	12,436,420
2023 and thereafter	12,436,420
Total undiscounted minimum future lease payments	19,241,076
Deferred rental liability on straight line amortization	183,952
Imputed interest	(3,764,431)
Total operating lease liability	15,660,597
Disclosed as:
Current portion	835,898
Non-current portion	14,824,699
Total	$ 15,660,597