Condensed Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Statements of Operations
Collaboration and grant revenue	$ 943	$ 1,205	$ 5,535	$ 3,778
Type of Revenue [Extensible List]	aptx:CollaborationAndGrantMember	aptx:CollaborationAndGrantMember	aptx:CollaborationAndGrantMember	aptx:CollaborationAndGrantMember
Operating expenses:
Research and development	$ 11,950	$ 8,067	$ 37,860	$ 24,930
General and administrative	3,782	1,318	7,853	3,819
Total operating expenses	15,732	9,385	45,713	28,749
Loss from operations	(14,789)	(8,180)	(40,178)	(24,971)
Other income	608	35	990	129
Net loss and comprehensive loss	$ (14,181)	$ (8,145)	$ (39,188)	$ (24,842)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.43)	$ (1.56)	$ (2.48)	$ (4.82)
Weighted-average number of common shares outstanding, basic and diluted (in shares)	33,191	5,232	15,789	5,159

The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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