Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 22,484	$ 45,206
General and administrative	11,918	4,039
Restructuring Charges	0	2,996
Total operating expenses	34,402	52,241
Loss from operations	(34,402)	(52,241)
Other income (expense):
Interest income	15	8
Interest expense	(20)	(166)
Gain on issuance of convertible notes		63
Change in fair value of convertible notes		(1,076)
Change in fair value of non-marketable equity securities	(892)
Gain on sale of PNAi technology	2,691
Total other income (expense)	1,794	(1,171)
Loss before provision for income taxes	(32,608)	(53,412)
Provision for income taxes	(1)	(1)
Net loss and comprehensive loss	$ (32,609)	$ (53,413)
Net loss per share attributable to common stockholders, basic and diluted	$ (2.43)	$ (166.93)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	13,435,706	319,963