Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2018	Aug. 31, 2015	Jul. 31, 2015	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic Value of option exercised				$ 100		$ 1,700
Inventory
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Amount of stock-based compensation capitalized				100		100
Former Executive
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Accelerated stock compensation expense				200	$ 500	$ 400	$ 1,000
Restricted Stock \| Common Stock \| Archer Daniels Midland Company
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Long-term purchase commitment, shares issued	300,000
Shares issued, vesting period									3 years 6 months
Stock-based compensation, shares vested						150,000
Unrecognized employee stock-based compensation									$ 1,800
Expected recognized over weighted-average remaining vesting period						1 year
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Recognized stock-based compensation expense				17,828		$ 17,828
Restricted Stock Units (RSUs) \| Certain Key Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of restricted stock issued						58,000
Restricted stock units, aggregate grant date fair value						$ 1,400
Recognized stock-based compensation expense				$ 1,100		$ 1,100
Shares vested upon performance condition met				36,000		36,000
2015 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares reserved for issuance			4,681,544
Number of shares available for future grant				4,121,726		4,121,726		4,599,005
Minimum percentage of voting rights of all classes of stock			10.00%
Percentage of statutory stock options			110.00%
Options expiration period			10 years
2015 Plan \| Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares vested upon performance condition met						208,976
2015 Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options expiration period			10 years
2015 Plan \| First Anniversary
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting period			4 years
Option vesting rights, percentage			25.00%
2015 Plan \| Thereafter
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option vesting rights, percentage			2.08%
2015 Plan \| Over Two Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting period			2 years
Option vesting rights, percentage			4.17%
2015 Plan \| Over Four Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting period			4 years
Option vesting rights, percentage			2.08%
2015 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of statutory stock options		85.00%
Description of ESPP						Under the 2015 ESPP our employees may purchase common stock through payroll deductions at a price equal to 85% of the lower of the fair market value of the stock at the beginning of the offering period or at the end of each applicable purchase period. The 2015 ESPP generally provides for offering periods of six months in duration with purchase periods ending on either May 15 or November 15. Contributions under the 2015 ESPP are limited to a maximum of 15% of an employee’s eligible compensation.
Percentage of maximum contributions employee's eligible compensation		15.00%
ESPP offering period		6 months
Description of offering period closing dates						The 2015 ESPP generally provides for offering periods of six months in duration with purchase periods ending on either May 15 or November 15
Shares issued under the plan								101,989
Weighted average price per share								$ 17.67
Employee stock purchase plan remain available for purchase						2,845,844
2013 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares reserved for issuance				0		0
Number of shares available for future grant				0		0

Aimmune Therapeutics, Inc. 10-Q