Subsequent Events (Details)	Nov. 29, 2018 USD ($)	Nov. 28, 2018 $ / shares shares	Oct. 24, 2018 $ / shares shares	Oct. 12, 2018 shares	Oct. 31, 2018 shares	Sep. 29, 2018 USD ($)	Dec. 30, 2017 USD ($)
Subsequent Events
Outstanding borrowings | $						$ 346,962,000	$ 437,625,000
Subsequent Event
Subsequent Events
Reverse stock split ratio				0.397
Increase in common stock shares authorized				200,000,000
Increase In Preferred Stock Shares Authorized				30,000,000
Shares issued				0
Subsequent Event | Restricted stock units (RSUs) | Non-employee director serving on the Board of Directors
Subsequent Events
Options granted (in shares)			16,693
Subsequent Event | Deferred stock units (DSUs) | Non-employee director serving on the Board of Directors
Subsequent Events
Options granted (in shares)			13,388
Subsequent Event | 2018 Plan
Subsequent Events
Shares reserved for future issuance					4,764,000
Subsequent Event | 2018 Plan | Time-based stock options
Subsequent Events
Options granted (in shares)			761,031
Exercise price per share | $ / shares			$ 18.00
Vesting period (in years)			4 years
Expiration period (in years)			10 years
Subsequent Event | Additional allotment option
Subsequent Events
Common stock sold by selling stockholders		918,830	2,400,000
Public offering, shares issued price (per share) | $ / shares		$ 18.00
Subsequent Event | Term Loan A, due 2021
Subsequent Events
Voluntary debt payments on principal | $	$ 2,400,000
Outstanding borrowings | $	342,500,000
Subsequent Event | Term Loan B, due 2022
Subsequent Events
Voluntary debt payments on principal | $	47,600,000
Outstanding borrowings | $	$ 0