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

Quarterly report pursuant to Section 13 or 15(d)

Related Party Transaction - Additional Information (Detail)

Related Party Transaction - Additional Information (Detail)								3 Months Ended	9 Months Ended	12 Months Ended		16 Months Ended	20 Months Ended
	Jul. 24, 2017 USD ($) $ / shares shares	Jul. 20, 2017 shares	Jul. 19, 2017 shares	Jul. 18, 2017 USD ($) $ / shares shares	Mar. 07, 2017 USD ($)	Sep. 30, 2015 USD ($) $ / shares shares	May 18, 2015 USD ($)	Mar. 31, 2018 USD ($) $ / shares	Sep. 30, 2016 USD ($)	Dec. 31, 2017 USD ($) $ / shares	Dec. 31, 2016 USD ($) NotesPayable	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Jul. 31, 2017 USD ($)
Related Party Transaction [Line Items]
Common stock, par value \| $ / shares								$ 0.001		$ 0.001
Ricanto, Ltd [Member]
Related Party Transaction [Line Items]
Consulting fees incurred, related parties									$ 100,000	$ 0
Related party consulting agreement, date of termination								Aug. 01, 2017
Accounts payable, related parties				$ 600,000				$ 0			$ 600,000	$ 600,000	$ 600,000
Shares issued to related party for services \| shares				475
Shares issued to related party, par value \| $ / shares				$ 0.01
Ricanto, Ltd [Member] \| OncoGenex Pharmaceuticals, Inc [Member] \| Common Stock
Related Party Transaction [Line Items]
Conversion of each outstanding share of Achieve common stock , shares converted \| shares				359.3053
Number of shares post-conversion \| shares				170,670
Chief Executive Officer [Member]
Related Party Transaction [Line Items]
Accounts payable, related parties								0
Notes payable, related parties											$ 200,000	200,000	200,000
Number of notes payable \| NotesPayable											2
Notes payable, rate of interest											3.50%
Notes payable repayment period											1 year
Outstanding principal, included in shareholder loans											$ 200,000	200,000	200,000
Accrued interest owed to related party								0			3,000	3,000	3,000
Salary paid													0
Chief Executive Officer [Member] \| Accrued Compensation [Member]
Related Party Transaction [Line Items]
Accrued salaries											700,000	700,000	700,000
Accrued salaries, common stock shares issued \| shares			238
Percentage of common stock issued in settlement of accrued salaries			50.00%
Percentage of cash payment in settlement of accrued salaries			50.00%
Chief Executive Officer [Member] \| Accrued Liabilities Other [Member]
Related Party Transaction [Line Items]
Accounts payable, related parties								300,000
Chief Executive Officer [Member] \| Convertible Notes Payable [Member]
Related Party Transaction [Line Items]
Shares issued to related party, par value \| $ / shares	$ 0.01
Debt conversion, converted instrument, amount	$ 200,000
Debt conversion, converted instrument, shares issued \| shares	146
Chief Executive Officer [Member] \| OncoGenex Pharmaceuticals, Inc [Member] \| Common Stock
Related Party Transaction [Line Items]
Conversion of each outstanding share of Achieve common stock , shares converted \| shares	359.3014		359.3025
Number of shares post-conversion \| shares	52,458		85,514
Lender
Related Party Transaction [Line Items]
Accounts payable, related parties								0			700,000	700,000	700,000
Notes payable, related parties					$ 20,000
Notes payable, rate of interest					3.50%
Notes payable repayment period					1 year
Accrued interest owed to related party								0			35,000	35,000	35,000
Debt conversion, converted instrument, amount	$ 800,000
Debt conversion, converted instrument, shares issued \| shares	586
Common stock, par value \| $ / shares	$ 0.01
Lender \| Convertible Promissory Note [Member]
Related Party Transaction [Line Items]
Notes payable, related parties							$ 2,700,000
Notes payable, rate of interest							3.50%
Debt conversion, converted instrument, amount						$ 2,000,000
Debt conversion, converted instrument, shares issued \| shares						4,500
Common stock, par value \| $ / shares						$ 0.01
Lender \| OncoGenex Pharmaceuticals, Inc [Member] \| Common Stock
Related Party Transaction [Line Items]
Conversion of each outstanding share of Achieve common stock , shares converted \| shares	359.3052
Number of shares post-conversion \| shares	1,827,426
Chief Financial Officer [Member]
Related Party Transaction [Line Items]
Salary paid												0
Chief Financial Officer [Member] \| Accrued Compensation [Member]
Related Party Transaction [Line Items]
Accrued salaries											$ 300,000	$ 300,000	$ 300,000
Accrued salaries, common stock shares issued \| shares		127
Percentage of common stock issued in settlement of accrued salaries		50.00%
Percentage of cash payment in settlement of accrued salaries		50.00%
Chief Financial Officer [Member] \| Accrued Liabilities Other [Member]
Related Party Transaction [Line Items]
Accounts payable, related parties								200,000
Chief Financial Officer [Member] \| OncoGenex Pharmaceuticals, Inc [Member] \| Common Stock
Related Party Transaction [Line Items]
Conversion of each outstanding share of Achieve common stock , shares converted \| shares		359.2992
Number of shares post-conversion \| shares		45,631
Michelle Griffin [Member] \| OncoGenex Pharmaceuticals, Inc [Member]
Related Party Transaction [Line Items]
Termination fee payable														$ 600,000
Michelle Griffin [Member] \| OncoGenex Pharmaceuticals, Inc [Member] \| Accrued Liabilities Other [Member]
Related Party Transaction [Line Items]
Accounts payable, related parties								$ 0