Annual report pursuant to Section 13 and 15(d)

Long-term Supply Contract (Details)

v3.10.0.1
Long-term Supply Contract (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 01, 2014
Commitments and Contingencies Disclosure [Abstract]        
Supply agreement liability $ 0 $ 22,250   $ 27,300
Gain on contract termination $ 20,612 $ 0 $ 0