Stock-based Compensation (Summary of Warrant Activity) (Detail) - Warrants [Member] - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding beginning, Number of Options	200,000
Granted, Number of Options
Outstanding ending, Number of Options	200,000	200,000
Exercisable, Number of Options	200,000
Outstanding beginning, Weighted Average Exercise Price	$ 13.32
Granted, Weighted Average Exercise Price
Outstanding ending, Weighted Average Exercise Price	13.32	$ 13.32
Exercisable, Weighted Average Exercise Price	$ 13.32
Weighted Average Remaining Contractual Life (in years)	5 years 10 months 24 days	6 years 4 months 24 days
Exercisable, Weighted Average Remaining Contractual Life (in years)	5 years 10 months 24 days
Nonvested
Granted, Options