Achieve Life Sciences, Inc. Quarterly report pursuant to Section 13 or 15(d)

License Agreements - Additional Information (Detail)			1 Months Ended	33 Months Ended
License Agreements - Additional Information (Detail)	Jan. 22, 2018 USD ($)	May 14, 2015	Jul. 31, 2016 USD ($)	Mar. 31, 2019 USD ($) g
Sopharma [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement expiry date		May 26, 2029
University of Bristol [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum amount payable under license agreement, tied to milestones			$ 3,200,000
Payments under license agreement				$ 125,000
License agreement expiry			2036-07
Volume of cytisine provided as an initial contribution \| g				100
University of Bristol [Member] \| Amendment to the University of Bristol License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum amount payable under license agreement, tied to milestones	$ 1,700,000
Payments under license agreement	$ 37,500
University of Bristol [Member] \| Minimum [Member] \| License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Patent expiry date			Feb. 05, 2036