Property, Plant and Mine Development, net - Summary of Property, Equipment and Mine Development (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
Property, equipment and mine development - net
Property and equipment, gross	[1],[2]	$ 217,071	$ 210,656
Accumulated depreciation and amortization		(92,621)	(85,397)
Total property, equipment and mine development - net		124,450	125,259
Accrued capital expenditures		2,800	3,800
Asset retirement costs
Property, equipment and mine development - net
Property and equipment, gross		3,847	3,412
Construction-in-progress
Property, equipment and mine development - net
Property and equipment, gross	[3]	15,279	11,965
Furniture and office equipment
Property, equipment and mine development - net
Property and equipment, gross		2,101	2,087
Leach pad and ponds
Property, equipment and mine development - net
Property and equipment, gross		5,649	5,649
Land
Property, equipment and mine development - net
Property and equipment, gross		242	242
Light vehicles and other mobile equipment
Property, equipment and mine development - net
Property and equipment, gross		2,553	2,553
Machinery and equipment
Property, equipment and mine development - net
Property and equipment, gross		44,125	43,364
Mill facilities and infrastructure
Property, equipment and mine development - net
Property and equipment, gross		31,966	31,408
Mineral interests and mineral rights
Property, equipment and mine development - net
Property and equipment, gross		18,228	18,228
Mine development
Property, equipment and mine development - net
Property and equipment, gross		91,422	90,089
Software and licenses
Property, equipment and mine development - net
Property and equipment, gross		1,659	1,659
Asset Value, Finance Lease
Property, equipment and mine development - net
Property and equipment, gross		1,800	1,800
Mexico
Property, equipment and mine development - net
Asset and development costs		1,900	2,400
Nevada
Property, equipment and mine development - net
Asset and development costs		$ 13,300	$ 9,600

[1] Includes $1.8 million of assets recorded under finance leases. Please see Note 13 for additional information.

[2] Includes accrued capital expenditures of $2.8 million and $3.8 million at March 31, 2020 and December 31, 2019, respectively.

[3] Includes Nevada pre-production stripping costs of $13.3 million and $9.6 million at March 31, 2020 and December 31, 2019, respectively. Mexico construction-in-progress was $1.9 million and $2.4 million at March 31, 2020 and December 31, 2019, respectively.