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Credit Facility - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Line of Credit Facility [Line Items]
Debt fee	$ 1,558		$ 1,558		$ 728
Accretion of debt discount	186	$ 60	331	$ 116
Amortization of deferred financing cost	55	$ 78	117	$ 138
Senior Secured Revolving Credit Facility
Line of Credit Facility [Line Items]
Revolving credit facility	55,000		55,000
Undrawn availability	16,000		16,000
Credit Facility \| Senior Secured Revolving Credit Facility
Line of Credit Facility [Line Items]
Long-term line of credit	$ 39,000		$ 39,000		$ 44,500