Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenues:
Collaboration revenue	$ 1,000	$ 1,564
Type of Revenue [Extensible List]	aptx:CollaborationRevenueMember	aptx:CollaborationRevenueMember
Operating expenses:
Research and development	$ 55,444	$ 32,835
General and administrative	20,090	19,494
Total operating expenses	75,534	52,329
Loss from operations	(74,534)	(50,765)
Other income (expense), net	(352)	712
Net loss and comprehensive loss	$ (74,886)	$ (50,053)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (1.11)	$ (1.02)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (1.11)	$ (1.02)
Weighted-average number of common shares outstanding, basic (in shares)	67,220	48,866
Weighted-average number of common shares outstanding, diluted (in shares)	67,220	48,866