Condensed Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Collaboration revenue				$ 1,000
Type of Revenue [Extensible List]	aptx:CollaborationRevenueMember	aptx:CollaborationRevenueMember	aptx:CollaborationRevenueMember	aptx:CollaborationRevenueMember
Operating expenses:
Research and development	$ 11,909	$ 14,796	$ 25,511	$ 25,110
General and administrative	5,196	5,070	10,973	10,046
Total operating expenses	17,105	19,866	36,484	35,156
Loss from operations	(17,105)	(19,866)	(36,484)	(34,156)
Other (income) expense, net	(195)	(47)	(224)	(111)
Interest expense	757		1,234
Net loss and comprehensive loss	$ (17,667)	$ (19,819)	$ (37,494)	$ (34,045)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.26)	$ (0.29)	$ (0.55)	$ (0.51)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.26)	$ (0.29)	$ (0.55)	$ (0.51)
Weighted-average number of common shares outstanding, basic (in shares)	67,716	67,381	67,716	66,716
Weighted-average number of common shares outstanding, diluted (in shares)	67,716	67,381	67,716	66,716