Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended
	May 08, 2018	Mar. 31, 2018
Subsequent Event [Line Items]
Initial incentive stock option to purchase		618,174
Restricted Stock Units (RSUs) [Member]
Subsequent Event [Line Items]
RSU granted		1,155,611
Subsequent Event [Member] | Chief Executive Officer [Member]
Subsequent Event [Line Items]
Employment starting date	May 08, 2018
Initial term of employment agreement	2 years
Renewable term of employment agreement	1 year
Notice period for employment agreement termination	60 days
Base salary	$ 570
Annual cash bonus	55.00%
Signing bonus	$ 50
Initial incentive stock option to purchase	800,000
Subsequent Event [Member] | Chief Executive Officer [Member] | Restricted Stock Units (RSUs) [Member]
Subsequent Event [Line Items]
RSU granted	200,000