Stockholders' Equity (2014 Shelf Registration Statement) - Additional Information (Detail) - USD ($)			6 Months Ended
	Feb. 04, 2015	Apr. 03, 2014	Jun. 30, 2017	Jan. 31, 2014
2014 Shelf Registration Statement [Member]
Stockholders' Equity [Line Items]
Maximum dollar amount of common stock to be issued under shelf registration statement				$ 100,000,000
Expiry date of common stock remaining under the shelf registration statement			Mar. 19, 2017
Underwritten Public Offering [Member]
Stockholders' Equity [Line Items]
Number of common stock sold in offering	11,500,000	13,023,750
Common stock issued, price per share	$ 3.25	$ 2.21
Gross proceeds from issuance of common stock	$ 37,400,000	$ 28,800,000
Offering expenses	$ 2,500,000	$ 2,100,000