Stockholders' Equity - Summary Of Changes In Securities (Detail) - shares	1 Months Ended			12 Months Ended
	Apr. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Dec. 31, 2014
Common Class A
Class Of Stock [Line Items]
Issuance of common stock less issuance costs, Shares				30,809,800
Issuance of stock to placement agent, Shares				3,087,324
Conversion of stock for placement agent in shares and exchange of warrant			(193,413)
Issuance of placement agent warrant associated with 2014 Securities Purchase Agreement			199,341
Common Class A | 2014 Other Creditor One
Class Of Stock [Line Items]
Promissory note agreed to convert	230,859
Common Class A | Options to Purchase
Class Of Stock [Line Items]
Conversion Of Warrant To Option To Purchase Of Common Stock	740,600
Common Class B
Class Of Stock [Line Items]
Stock approved for conversion to Class A common stock.				8,295,402
Issuance of stock to placement agent, Shares	763,151	763,151		763,151
Series C Preferred Stock
Class Of Stock [Line Items]
Stock approved for conversion to Class A common stock.				5,754,984
Prior to 2014 Securities Purchase Agreement | Common Class A
Class Of Stock [Line Items]
Share balance	1,158,394
Prior to 2014 Securities Purchase Agreement | Common Class A | Outstanding Warrants
Class Of Stock [Line Items]
Share balance	763,841
Prior to 2014 Securities Purchase Agreement | Common Class A | Options to Purchase
Class Of Stock [Line Items]
Share balance	3,056,702
Prior to 2014 Securities Purchase Agreement | Common Class B
Class Of Stock [Line Items]
Share balance	1,763,609
2014 Securities Purchase Agreement | Common Class A
Class Of Stock [Line Items]
Common stock issued for placement agent commission	34,715
2014 Securities Purchase Agreement | Common Class A | 2014 Other Creditor One
Class Of Stock [Line Items]
Stock approved for conversion to Class A common stock.	345,228
2014 Securities Purchase Agreement | Common Class A | Outstanding Warrants
Class Of Stock [Line Items]
Exchange of Founder Warrant	(156,109)
Issuance of common stock less issuance costs, Shares	1,245,881
Conversion of stock for placement agent in shares and exchange of warrant	(193,413)
Issuance of placement agent warrant associated with 2014 Securities Purchase Agreement	199,341
2014 Securities Purchase Agreement | Common Class A | 2013 Promissory Note | Outstanding Warrants
Class Of Stock [Line Items]
Promissory note agreed to convert	192,865
2014 Securities Purchase Agreement | Common Class A | 2009 Convertible Notes
Class Of Stock [Line Items]
Promissory note agreed to convert	985,229
2014 Securities Purchase Agreement | Common Class A | CA Warrant and PA Warrant
Class Of Stock [Line Items]
Warrant exchanged	3,052,608
2014 Securities Purchase Agreement | Common Class A | Side Agreement Notes
Class Of Stock [Line Items]
Promissory note agreed to convert	192,341
2014 Securities Purchase Agreement | Series C Preferred Stock
Class Of Stock [Line Items]
Issuance of common stock less issuance costs, Shares	4,983,526
2014 Securities Purchase Agreement | Series C Preferred Stock | 2013 Promissory Note
Class Of Stock [Line Items]
Promissory note agreed to convert	771,458
After Closing Of Two Thousand Fourteen Securities Purchase Agreement | Common Class A
Class Of Stock [Line Items]
Share balance	5,768,515
After Closing Of Two Thousand Fourteen Securities Purchase Agreement | Common Class A | Outstanding Warrants
Class Of Stock [Line Items]
Share balance	2,052,406
After Closing Of Two Thousand Fourteen Securities Purchase Agreement | Common Class A | Options to Purchase
Class Of Stock [Line Items]
Share balance	3,797,302
After Closing Of Two Thousand Fourteen Securities Purchase Agreement | Common Class B
Class Of Stock [Line Items]
Share balance	2,526,760
After Closing Of Two Thousand Fourteen Securities Purchase Agreement | Series C Preferred Stock
Class Of Stock [Line Items]
Share balance	5,754,984