Condensed Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Consolidated Statements of Operations
Collaboration and grant revenue	$ 2,128	$ 1,428	$ 4,593	$ 2,573
Type of Revenue [Extensible List]	aptx:CollaborationAndGrantMember	aptx:CollaborationAndGrantMember	aptx:CollaborationAndGrantMember	aptx:CollaborationAndGrantMember
Operating expenses:
Research and development	$ 13,686	$ 8,201	$ 25,911	$ 16,862
General and administrative	2,022	1,268	4,071	2,501
Total operating expenses	15,708	9,469	29,982	19,363
Loss from operations	(13,580)	(8,041)	(25,389)	(16,790)
Other income	245	42	382	94
Net loss and comprehensive loss	$ (13,335)	$ (7,999)	$ (25,007)	$ (16,696)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (1.83)	$ (1.55)	$ (3.95)	$ (3.26)
Weighted-average number of common shares outstanding, basic and diluted (in shares)	7,275	5,159	6,332	5,122

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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