Equity (Detail) - USD ($) $ in Thousands		6 Months Ended
	Mar. 11, 2016	Jun. 30, 2016
Subsidiary, Sale of Stock [Line Items]
Direct offering costs		$ 830
FOLLOW-ON PUBLIC OFFERING
Subsidiary, Sale of Stock [Line Items]
Direct offering costs	$ 800
Net proceeds received	$ 141,500
Common Stock | FOLLOW-ON PUBLIC OFFERING
Subsidiary, Sale of Stock [Line Items]
Shares of common stock included in offering	7,500,000