Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net loss	$ (30,362)	$ (18,998)
Adjustment to reconcile net loss to net cash used in operating activities
Depreciation	127	78
Share-based compensation expense	12,731	10,476
Gain on common stock warrant liabilities	(83)
Loss on investment securities	28
Changes in operating assets and liabilities:
Prepaid expenses and other currents assets	295	53
Accounts payable	(42)	190
Accrued expenses and other liabilities	4,660	209
Net cash used in operating activities	(12,646)	(7,992)
Investing activities:
Acquisition of property, plant and equipment	(11,460)	(10,690)
Issuance of note receivable		(115)
Repayment of note receivable		115
Cash received in reverse recapitalization		26,774
Purchase of investments	(55,100)	(54)
Net cash (used in) provided by investing activities	(66,560)	16,030
Financing activities:
Proceeds from equity issuance	79,055	30,100
Equity issuance costs	(1,653)	(5,953)
Shares repurchased related to share-based compensation	(19)
Net cash provided by financing activities	77,383	24,147
Net (decrease) increase in cash and cash equivalents	(1,823)	32,185
Cash and cash equivalents – beginning of period	35,703	12,524
Cash and cash equivalents – end of period	33,880	44,709
Non-cash investing activities:
Accounts payable for acquisition of property, plant and equipment	656	1,266
Accrued liabilities for acquisition of property, plant and equipment	6,056	$ 1,845
Non-cash financing activities:
Accounts payable for equity issuance costs	150
Accrued liabilities for equity issuance costs	301
Accretion of deemed dividends Series A Convertible Preferred Stock	$ 271