Warrants - Additional Information (Detail) $ / shares in Units, $ in Millions							6 Months Ended	12 Months Ended
	May 10, 2017 $ / shares shares	Apr. 28, 2017 $ / shares shares	Aug. 14, 2015 $ / shares shares	Sep. 26, 2014 $ / shares shares	Mar. 22, 2013 USD ($) Investor $ / shares shares	Jan. 17, 2012 $ / shares shares	Jun. 30, 2017 $ / shares shares	Dec. 31, 2013 shares	Sep. 03, 2013 shares
Class of Warrant or Right [Line Items]
Offering price | $ / shares		$ 1.00
Warrants to purchase common shares		24,900,000
Warrant, expiration period				7 years
Warrants outstanding									1,200,000
Warrants exercised		0					0
Warrants, exercise period description							the holders of Series A Warrants will have 10 business days after written notice to exercise, in whole or in part, their Series A Warrants. Any Series A Warrants that remain unexercised after such 10 business day period will expire.
Minimum [Member]
Class of Warrant or Right [Line Items]
Percentage of warrants exercisability limitation percentage							4.99%
Outstanding voting stock acquisition minimum threshold percentage to assume warrant obligations							50.00%
Series A Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants, exercise price | $ / shares		$ 1.00
Series B Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants, exercise price | $ / shares		$ 1.00					$ 1.00
Common Stock [Member]
Class of Warrant or Right [Line Items]
Number of common stock or warrants in each unit		1
Common Stock [Member] | Series A Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants, exercise price | $ / shares		$ 1.00
Number of common stock or warrants in each unit		1
Common Stock [Member] | Series B Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants, exercise price | $ / shares		$ 1.00
Number of common stock or warrants in each unit		0.75
Amended Loan Agreement [Member]
Class of Warrant or Right [Line Items]
Warrants, exercise price | $ / shares			$ 3.10	$ 4.015
Warrant, expiration period							7 years
Warrants exercised							0
Common stock warrants issued			112,903	38,325
Stock Purchase Agreement 2013 [Member] | 2013 PIPE investors [Member]
Class of Warrant or Right [Line Items]
Number of investors | Investor					17
Stock issued, shares					2,420,000
Offering price | $ / shares					$ 1.25
Proceeds from PIPE | $					$ 3.0
Warrants to purchase common shares					1,209,600
Warrants, exercise price | $ / shares					$ 1.65
Warrant, expiration period					5 years
Merger Agreement [Member]
Class of Warrant or Right [Line Items]
Exchange ratio									1.1533
Loan and Security Agreement [Member]
Class of Warrant or Right [Line Items]
Warrants to purchase common shares						430,815
Loan and Security Agreement [Member] | Term Loan [Member]
Class of Warrant or Right [Line Items]
Warrant, expiration period	5 years
Warrants exercised							0
Loan and Security Agreement [Member] | Term Loan [Member] | First Tranche [Member]
Class of Warrant or Right [Line Items]
Warrants to purchase common shares	1,244,746
Warrants, exercise price | $ / shares	$ 1.00
Related Parties [Member] | Stock Purchase Agreement 2013 [Member] | 2013 PIPE investors [Member]
Class of Warrant or Right [Line Items]
Stock issued, shares					1,280,000
Warrants to purchase common shares					640,000
Warrants exercised							0
Silicon Valley Bank and Oxford Finance LLC [Member]
Class of Warrant or Right [Line Items]
Warrants to purchase common shares						279,588
Warrants, exercise price | $ / shares						$ 1.45
Warrant, expiration period						10 years
Warrants exercised							0	139,794
Stock issued due to exercise of options								112,766