Equity Incentive Plan - Schedule of Stock Option Activity Under 2016 Plan (Detail) - 2016 Plan [Member] - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding, beginning balance	411,480
Options granted	67,050
Options forfeited	(32,860)
Options expired	(8,640)
Cancelled	(437,030)
Options outstanding, ending balance		411,480
Weighted average exercise price, beginning balance	$ 100
Weighted average exercise price, granted	90
Weighted average exercise price, forfeited	99
Weighted average exercise price, expired	99
Weighted average exercise price, cancelled	$ 100
Weighted average exercise price, ending balance		$ 100
Weighted average remaining contractual term, balance		8 years 3 months 18 days