Condensed Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 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	$ 10,008	$ 16,278	$ 35,519	$ 41,388
General and administrative	4,649	4,928	15,622	14,974
Total operating expenses	14,657	21,206	51,141	56,362
Loss from operations	(14,657)	(21,206)	(51,141)	(55,362)
Other (income) expense, net	(208)	(47)	(432)	(158)
Interest expense	854	72	2,088	72
Net loss and comprehensive loss	$ (15,303)	$ (21,231)	$ (52,797)	$ (55,276)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.23)	$ (0.31)	$ (0.78)	$ (0.82)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.23)	$ (0.31)	$ (0.78)	$ (0.82)
Weighted-average number of common shares outstanding, basic (in shares)	67,716	67,716	67,716	67,053
Weighted-average number of common shares outstanding, diluted (in shares)	67,716	67,716	67,716	67,053