Note 6 - Other Non-current Assets (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

Schedule of Other Assets, Noncurrent [Table Text Block]

	March 31,		December 31,
	2022		2021
Permitting costs(1)	$	7,784	$	7,644
Enterprise resource planning system, net		—		354
Rio Grande Site Lease initial direct costs		14,877		13,314
Total other non-current assets, net	$	22,661	$	21,312