CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net loss	$ (41,307)	$ (43,241)	$ (5,995)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	367	460	632
Accretion related to marketable securities	(170)	239	154
Stock-based compensation	2,692	4,232	5,747
Gain from sale of property and equipment	(22)
Gain on deconsolidation of Angel Pharmaceuticals			(37,459)
Loss from equity method investment	10,005	4,831	234
Changes in operating assets and liabilities:
Accounts receivable - related party	(81)	(507)
Prepaid and other current assets	581	(277)	285
Operating lease right-of-use asset	973	(1,542)	679
Other assets	107	178	99
Accounts payable	411	(1,902)	1,019
Accrued and other liabilities	467	(523)	705
Operating lease liability	(1,046)	1,337	(878)
Net cash used in operating activities	(27,023)	(36,715)	(34,778)
Cash flows from investing activities
Purchases of marketable securities	(66,191)	(9,357)	(42,540)
Sales of marketable securities			1,009
Maturities of marketable securities	43,162	30,922	86,376
Purchases of property and equipment	(269)	(5)	(76)
Proceeds from sale of property and equipment	22
Net cash provided by (used in) investing activities	(23,276)	21,560	44,769
Cash flows from financing activities
Proceeds from issuance of common stock, net (includes $4,850 in aggregate gross proceeds from related parties for the year ended December 31, 2021)		31,989
Proceeds from issuance of common stock in connection with at-the-market offering, net		28,954	1,222
Proceeds from exercise of common stock options		1,215	88
Net cash provided by financing activities		62,158	1,310
Net increase (decrease) in cash and cash equivalents	(50,299)	47,003	11,301
Cash and cash equivalents at beginning of the period	63,458	16,455	5,154
Cash and cash equivalents at end of the period	$ 13,159	63,458	$ 16,455
Supplemental disclosures of cash flow information
Purchases of property and equipment incurred but not paid		$ 5