Stockholders' Equity - Additional Information (Detail) - USD ($)			3 Months Ended			6 Months Ended
	Jan. 06, 2017	Jan. 05, 2017	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 09, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument			0		0	0	0
Preferred stock, shares authorized			10,000,000			10,000,000			10,000,000
Number of shares acquired	2,750,371					2,750,371
Number of warrants outstanding			14,077,779			14,077,779
Series B Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, shares outstanding			0			0			5,737
Convertible preferred stock, shares issued			0			0			5,737
Preferred stock, shares authorized									8,100
Series C Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, shares outstanding			0			0			0
Convertible preferred stock, shares issued			0			0			0
Preferred stock, shares authorized		1,800,000	1,800,000			1,800,000
Preferred stock voting rights						No voting rights, with certain exceptions
Other dividends paid		$ 0
Number of shares acquired	1,118,224					1,118,224
Shares issued upon conversion			1			1		1
Common Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument				6,374,444
Warrants With Exercise Price $39.00 [Member]
Class of Stock [Line Items]
Exercise prices			$ 39.00			$ 39.00
Number of warrants outstanding			462			462