Note 7 - Other Non-current Assets (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

Schedule of Other Assets, Noncurrent [Table Text Block]

	March 31,		December 31,
	2020		2019
Permitting costs (1)	$	7,315	$	2,621
Enterprise resource planning system, net		2,861		3,181
Rio Grande Site Lease initial direct costs		2,501		946
Total other non-current assets, net	$	12,677	$	6,748