Achieve Life Sciences, Inc. Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Assets
Total assets	$ 47,308us-gaap_AssetsFairValueDisclosure	$ 39,536us-gaap_AssetsFairValueDisclosure
Warrant [Member]
Liabilities
Liabilities	3,002	214
Cash [Member]
Assets
Total assets	16,481	10,575
Money market securities [Member]
Assets
Total assets	11,416	4,018
Restricted cash [Member]
Assets
Total assets	251	314
Corporate bonds and commercial paper [Member]
Assets
Total assets	19,160	24,629
Level 1 [Member]
Assets
Total assets	28,148	14,907
Level 1 [Member] \| Cash [Member]
Assets
Total assets	16,481	10,575
Level 1 [Member] \| Money market securities [Member]
Assets
Total assets	11,416	4,018
Level 1 [Member] \| Restricted cash [Member]
Assets
Total assets	251	314
Level 2 [Member]
Assets
Total assets	19,160	24,629
Level 2 [Member] \| Corporate bonds and commercial paper [Member]
Assets
Total assets	19,160	24,629
Level 3 [Member] \| Warrant [Member]
Liabilities
Liabilities	$ 3,002	$ 214