Inventories - Schedule of inventory (Details) $ in Thousands	Mar. 31, 2021 USD ($) oz	Dec. 31, 2020 USD ($) oz
Amount
Materials and supplies | $	$ 6,282	$ 6,449
Merrill-Crowe process plant | $	5,753	4,810
Carbon-in-column | $	2,750	299
Finished good (doré and off-site carbon) | $	4,165	1,309
Total | $	$ 18,950	$ 12,867
Gold Ounces
Materials and supplies | oz	0	0
Merrill-Crowe process plant | oz	3,300	2,587
Carbon-in-column | oz	1,703	166
Finished good (doré and off-site carbon) | oz	2,489	710
Total | oz	7,492	3,463