Note 6 - Other Non-current Assets (Tables)

6 Months Ended

Jun. 30, 2021

Notes Tables

Schedule of Other Assets, Noncurrent [Table Text Block]

	June 30,		December 31,
	2021		2020
Permitting costs(1)	$	7,409	$	7,385
Enterprise resource planning system, net		1,097		1,805
Rio Grande Site Lease initial direct costs		10,189		7,109
Total other non-current assets, net	$	18,695	$	16,299