Stock options, restricted stock and performance stock options - Stock Options (Details)			12 Months Ended			18 Months Ended
	Jan. 01, 2017 shares	Jan. 01, 2016 shares	Dec. 31, 2016 $ / shares shares	Dec. 31, 2015 $ / shares	Dec. 31, 2014 $ / shares	Dec. 31, 2016 shares	Jul. 31, 2015 shares	Nov. 30, 2009 shares
Employee stock options | Performance based
Stock options, restricted stock and performance stock options
Vesting period			3 years
Stock options
Stock options, restricted stock and performance stock options
Vesting period			4 years
Weighted average key assumptions used in determining the fair value of options granted
Estimated dividend yield (as a percent)			0.00%	0.00%	0.00%
Expected stock price volatility (as a percent)			60.00%	60.00%	60.00%
Expected life of option in years			6 years 1 month 24 days	5 years	5 years
Weighted-average option fair value at grant (in dollars per share) | $ / shares			$ 5.800	$ 9.723	$ 2.884
Stock options | Weighted average
Weighted average key assumptions used in determining the fair value of options granted
Weighted-average risk-free interest rate (as a percent)			1.18%	1.60%	1.77%
Neos Therapeutics, Inc. 2009 Equity Plan
Stock options, restricted stock and performance stock options
Shares reserved for issuance under the plan								1,375,037
Neos Therapeutics, Inc. 2009 Equity Plan | Stock options
Stock options, restricted stock and performance stock options
Expiration period			10 years
Expiration period of unexercised vested award after termination of employment			90 days
Neos Therapeutics, Inc. 2015 Stock Option and Incentive Plan
Stock options, restricted stock and performance stock options
Shares reserved for issuance under the plan							767,330
Increase in number of shares reserved and available for issuance		800,797
Increase to the number of shares reserved and available for issuance as a percentage of outstanding common stock (as a percent)		5.00%
Stock option exercise price, minimum expressed as percentage of fair market value on grant date			100
Shares related to forfeited prior plan options transferred into shares available under current plan						7,500
Share of restricted stock transferred into shares available under current plan						18,906
Shares available for grant			210,599			210,599
Neos Therapeutics, Inc. 2015 Stock Option and Incentive Plan | Subsequent event
Stock options, restricted stock and performance stock options
Shares reserved for issuance under the plan	1,013,648
Increase in number of shares reserved and available for issuance	803,049
Neos Therapeutics, Inc. 2015 Stock Option and Incentive Plan | Stock options
Stock options, restricted stock and performance stock options
Expiration period			10 years
Expiration period of unexercised vested award after termination of employment			90 days