CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Assets:
Cash	$ 30,220	$ 56,363
Accounts receivable	1,463	426
Inventories - Note 4	19,087	12,867
Ore on leach pads- Note 4	37,664	38,041
Prepaids and other - Note 5	6,236	4,303
Current assets	94,670	112,000
Ore on leach pads, non-current - Note 4	7,298	7,243
Plant, equipment, and mine development, net - Note 6	68,624	60,223
Restricted cash - Note 7	34,855	39,677
Other assets, non-current - Note 5	14,578	13,483
Total assets	220,025	232,626
Liabilities:
Accounts payable and accrued expenses	15,618	12,280
Debt, net - Note 9	9,613	5,120
Royalty obligation - Note 10	423	124
Other liabilities - Note 8	5,427	4,157
Current liabilities	31,081	21,681
Warrant liabilities, non-current - Note 11	4,961	15,389
Debt, net, non-current - Note 9	147,856	142,665
Royalty obligation, non-current - Note 10	29,432	29,839
Asset retirement obligation, non-current - Note 12	4,989	4,785
Other liabilities, non-current - Note 8	1,298	1,650
Total liabilities	219,617	216,009
Commitments and contingencies - Note 20
Stockholders' (deficit) equity
Common stock, $0.0001 par value; 400,000,000 shares authorized; 59,977,318 issued and outstanding at June 30, 2021; and 59,901,306 issued and outstanding at December 31, 2020	6	6
Additional paid-in capital	539,276	537,370
Accumulated deficit	(538,874)	(520,759)
Total stockholders' equity	408	16,617
Total liabilities and stockholders' equity	$ 220,025	$ 232,626