Warrants - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified				0 Months Ended	9 Months Ended	12 Months Ended	0 Months Ended	9 Months Ended		0 Months Ended	9 Months Ended	12 Months Ended
	Apr. 30, 2014	Apr. 14, 2014	Sep. 03, 2013	Jan. 17, 2012 Silicon Valley Bank and Oxford Finance LLC [Member]	Sep. 30, 2014 Silicon Valley Bank and Oxford Finance LLC [Member]	Dec. 31, 2013 Silicon Valley Bank and Oxford Finance LLC [Member]	Sep. 26, 2014 Amended and Restated Loan Agreement [Member]	Sep. 30, 2014 Amended and Restated Loan Agreement [Member]	Sep. 03, 2013 Merger Agreement [Member]	Mar. 22, 2013 2013 PIPE investors [Member] Stock Purchase Agreement 2013 [Member] Investor	Sep. 30, 2014 2013 PIPE investors [Member] Stock Purchase Agreement 2013 [Member] Related Parties [Member]	Dec. 31, 2013 2013 PIPE investors [Member] Stock Purchase Agreement 2013 [Member] Related Parties [Member]
Class of Warrant or Right [Line Items]
Number of investors										17
Stock issued, shares										2,420,000
Stock issued, price per share	$ 4.00	$ 4.00								$ 1.25
Proceeds from PIPE										$ 3.0
Warrants to purchase common shares				279,586						1,209,600
Warrants, exercise price				$ 1.45			$ 4.015			$ 1.65
Warrant, expiration period				10 years				7 years		5 years
Warrants outstanding			1,200,000
Warrants exercised					0	139,793		0			10,000	54,000
Other expense				$ 1.8
Exchange ratio									1.1533
Stock issued due to exercise of options						112,766
Common stock warrants issued							38,325