Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (29,500)	$ (34,744)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,404	2,120
Loss on disposal of equipment	281	0
Noncash interest expense	90	116
Share-based compensation	4,016	915
Change in fair value of derivative liability	556	104
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,191)	435
Other long-term assets	(290)	(56)
Accounts payable	432	(1,101)
Accrued expenses	(1,551)	509
Deferred rent		(39)
Settlement of derivative liability	(1,050)
Net cash used in operating activities	(26,803)	(31,741)
Cash flows from investing activities:
Purchases of property and equipment	(106)	(466)
Proceeds from sale of equipment	144
Net cash provided by (used in) investing activities	38	(466)
Cash flows from financing activities:
Proceeds from issuance of common stock	60,482
Issuance costs from issuance of common stock	(6,319)
Repayment of borrowings under loan	(5,625)
Net cash provided by financing activities	48,538
Net change in cash, cash equivalents and restricted cash	21,773	(32,207)
Cash, cash equivalents and restricted cash at beginning of year	25,566	57,773
Cash, cash equivalents and restricted cash at end of year	47,339	25,566
Supplemental disclosure of cash flow information
Cash paid for interest	854	$ 1,115
Supplemental disclosure of financing activities
Conversion of preferred units	$ 129,870