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Credit Facility - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Line of Credit Facility [Line Items]
Debt fee	$ 1,815		$ 1,815		$ 728
Accretion of debt discount	186	$ 65	517	$ 181
Amortization of deferred financing cost	54	$ 85	172	$ 223
Senior Secured Revolving Credit Facility
Line of Credit Facility [Line Items]
Revolving credit facility	52,500		52,500
Undrawn availability	30,000		30,000
Credit Facility \| Senior Secured Revolving Credit Facility
Line of Credit Facility [Line Items]
Long-term line of credit	$ 22,500		$ 22,500		$ 44,500