Notes Payable to Related Parties - Additional Information (Detail) - USD ($)			9 Months Ended	12 Months Ended
	Sep. 27, 2018	Aug. 15, 2018	Sep. 30, 2018	Dec. 31, 2017
Notes Payable to Related Parties [Line Items]
Gain (loss) on extinguishment of debt		$ 0
Total face amount			$ 6,107,000	$ 8,940,000
Notes Payable to Related Parties [Member]
Notes Payable to Related Parties [Line Items]
Total face amount			400,000	$ 3,992,000
Notes Payable to Related Parties [Member] | Promissory notes due 10/1/18 [Member]
Notes Payable to Related Parties [Line Items]
Total face amount			$ 400,000
Notes payable, maturity date			Oct. 01, 2018	Oct. 01, 2018
Executive Officer [Member] | Notes Payable to Related Parties [Member] | Promissory notes due 10/1/18 [Member]
Notes Payable to Related Parties [Line Items]
Total face amount	$ 400,000,000
Notes payable, maturity date	Oct. 01, 2018
Loan fee	$ 4,000,000