CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (14,803)	$ (32,117)
Adjustments to reconcile net loss to net cash from operating activities:
Stock-based compensation expense	5,017	4,963
Non-cash interest expense	182	270
Depreciation and amortization expense	2,128	2,759
Non-cash manufacturing expense	462
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	757	(947)
Prepaid manufacturing services	13
Operating right-of-use assets	654	484
Accounts payable	(650)	(54)
Accrued expenses	(1,900)	(459)
Deferred revenue	(26,016)	(11,835)
Operating lease liabilities	(1,292)	(384)
Net cash used in operating activities	(35,448)	(37,320)
Cash flows from investing activities:
Purchases of property and equipment	(353)	(2,365)
Net cash used in investing activities	(353)	(2,365)
Cash flows from financing activities:
Proceeds from exercise of common stock options		2,770
Net cash received from Employee Stock Purchase Program (ESPP)	126
Proceeds from issuance of common stock, net of issuance costs	522	61,681
Net cash provided by financing activities	648	64,451
Net (decrease) increase in cash, cash equivalents and restricted cash	(35,153)	24,766
Cash, cash equivalents and restricted cash, beginning of period	81,108	93,085
Cash, cash equivalents and restricted cash, end of period	45,955	117,851
Supplemental disclosures:
Cash paid for interest	516	1,138
Non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable and accrued expenses	4	368
Deferred offering costs included in accrued expenses		16
Reconciliation to amounts within the consolidated balance sheets
Cash and cash equivalents	41,785	113,681
Restricted cash	4,170	4,170
Cash, cash equivalents and restricted cash at end of period	$ 45,955	$ 117,851