Fair Value Measurements - Schedule of Assumptions Used to Value Liability (Detail) - Second Tranche Transaction Liability [Member]	Jun. 25, 2018 shares	Mar. 28, 2018 shares
Estimated date of stockholder approval		2018-06
Estimated number of units issuable	20,184,224	26,900,000
Measurement Input, Price Volatility % [Member]
Measurement input		54.20
Measurement Input, Risk Free Interest Rate % [Member]
Measurement input		1.70
Measurement Input, Valuation Date Stock Price % [Member]
Measurement input	1.93	1.07