Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 18,846	$ 35,703
Investments	5,088	5,063
Prepaid expenses and other current assets	2,195	2,099
Total current assets	26,129	42,865
Property, plant and equipment, net	86,060	73,226
Total assets	112,189	116,091
Current liabilities
Accounts payable	623	726
Share-based compensation liability	7,548	1,815
Accrued liabilities and other current liabilities	9,892	5,856
Total current liabilities	18,063	8,397
Non-current compensation liabilities		2,015
Non-current share-based compensation liability		2,587
Total liabilities	18,063	12,999
Commitments and contingencies (Note 9)
Stockholders’ equity
Preferred stock, $0.0001 par value, 1.0 million shares authorized, none issued
Common stock, $0.0001 par value Authorized: 480.0 million shares at June 30, 2018 and December 31, 2017 Issued and outstanding: 106.4 million shares and 106.3 million shares at June 30, 2018 and December 31, 2017, respectively	11	11
Additional paid-in-capital	169,454	158,738
Accumulated deficit	(75,339)	(55,617)
Accumulated other comprehensive loss		(40)
Total stockholders’ equity	94,126	103,092
Total liabilities and stockholders’ equity	$ 112,189	$ 116,091