Stockholders' Equity - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended		3 Months Ended
	Mar. 31, 2015	Apr. 30, 2013	Mar. 31, 2016	Aug. 31, 2011
Controlled Equity Offering Facilities [Member]
Stockholders Equity [Line Items]
Issuance of common stock, offering value				$ 20.0
Common stock sales agreement, date			2011-08
Issuance of common stock, remaining offering value			$ 18.2
Controlled Equity Offering Facilities [Member] | Common Stock [Member]
Stockholders Equity [Line Items]
Issuance of preferred stock, shares			0
Additional Controlled Equity Offerings Facilities [Member]
Stockholders Equity [Line Items]
Increase in aggregate controlled equity offering agreement as per amendment	$ 30.0	$ 30.0
Issuance of common stock, commission percentage		3.00%
Common stock sales agreement amended, date			2013-04
Common stock sales agreement further amended, date			2015-03
Issuance of common stock, commission percentage, maximum	3.00%