Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended
	Feb. 15, 2018	Feb. 13, 2018	Mar. 31, 2018
Stockholders Equity Disclosure [Line Items]
Net proceeds from sale of common stock	$ 106.8
Common Stock
Stockholders Equity Disclosure [Line Items]
Firm commitment underwritten public offering shares		2,941,176
Issuance of stock, shares	3,382,352		3,382,352
Common stock price, per share	$ 34.00
Common Stock | Overallotment Option
Stockholders Equity Disclosure [Line Items]
Issuance of stock, shares	441,176