Stock-Based Compensation - Summary of Stock Option Activity (Detail) - Stock Options [Member] shares in Thousands	3 Months Ended
	Mar. 31, 2019 $ / shares shares
Summary Of Stock Option Activities [Line Items]
Options Outstanding, Beginning balance, Shares | shares	423,534
Options Outstanding, Cancelled/expired | shares	(100,262)
Options Outstanding, Ending balance, Shares | shares	323,272
Options Exercisable, Ending balance, Shares | shares	318,541
Weighted Average Exercise Price, Beginning balance | $ / shares	$ 7.15
Weighted Average Exercise Price, Options cancelled/expired | $ / shares	7.16
Weighted Average Exercise Price, Ending balance | $ / shares	7.14
Weighted Average Exercise Price, Exercisable | $ / shares	$ 7.16