Debt - Summary of Debt (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total debt	$ 8.6	$ 17.2
CIBC loan due June 29, 2020, effective borrowing rate of 6.55% and 5.93% [Member] | Loan Agreement [Member]
Debt Instrument [Line Items]
Total debt	8.4	16.9
Furniture loan due May 2021, effective borrowing rate of 9.10% [Member]
Debt Instrument [Line Items]
Total debt	0.1	0.1
Furniture loan due May 2021, effective borrowing rate of 9.55% [Member]
Debt Instrument [Line Items]
Total debt	$ 0.1	0.1
Furniture loan due July 2019, effective borrowing rate of 13.98% [Member]
Debt Instrument [Line Items]
Total debt		$ 0.1