Revenue Deferred Revenue and Related Costs Oxide Plant Lease and Oxide Plant Lease Costs (Details) $ / shares in Units, $ in Thousands, shares in Millions				1 Months Ended			3 Months Ended
	Dec. 03, 2019 $ / item	Dec. 02, 2019 $ / item	Aug. 02, 2017 USD ($) $ / shares shares	Jan. 31, 2020 $ / item	Dec. 31, 2019 USD ($)	Aug. 31, 2017	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)
Oxide plant lease							$ 1,196	$ 1,932
Lease related costs							564	597
Increase (Decrease) in Deferred Revenue							(118)	(73)
Lease payment							125
Variable fee (per tonne) | $ / item	11.00	22.00
Minimum
Variable fee (per tonne) | $ / item				11.00
Maximum
Variable fee (per tonne) | $ / item				22.00
Oxide Plant
Renewal term			2 years
Expected lease proceeds			$ 1,000				100	$ 100
Gross proceeds from common stock sale			$ 1,000
Common stock issued (in shares) | shares			1.8
Sale price (in dollars per shares) | $ / shares			$ 0.55
Volume weighted average stock price period			30 days
Termination notice period						120 days
Deferred revenue							200
Increase (Decrease) in Deferred Revenue					$ 74		$ (170)