Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (21,109)	$ (28,132)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,335	1,599
Loss on disposal of equipment	8	5
Noncash interest expense	72	93
Share-based compensation	2,966	689
Change in fair value of derivative liability	556	96
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,379)	228
Other long-term assets	25	(26)
Accounts payable	194	(1,103)
Accrued expenses	(1,848)	401
Settlement of derivative liability	(1,050)
Net cash used in operating activities	(20,230)	(26,150)
Cash flows from investing activities:
Purchases of property and equipment	(23)	(281)
Proceeds from sale of equipment	55
Net cash provided by (used in) investing activities	32	(281)
Cash flows from financing activities:
Proceeds from issuance of common units	60,482
Issuance costs from issuance of common units	(6,319)
Repayment of borrowings under loan	(3,750)
Net cash provided by financing activities	50,413
Net change in cash, cash equivalents and restricted cash	30,215	(26,431)
Cash, cash equivalents and restricted cash at beginning of period	25,566	57,773
Cash, cash equivalents and restricted cash at end of period	55,781	31,342
Supplemental disclosure of cash flow information
Cash paid for interest	686	$ 851
Supplemental disclosure of financing activities
Conversion of preferred units	129,870
Deferred offering costs included in accrued expenses	$ (116)