Preferred Stock Warrants - Summary of Redeemable Convertible Preferred Stock Warrants (Detail) - $ / shares
|
6 Months Ended |
|
Jun. 30, 2015 |
Dec. 31, 2014 |
| Class of Warrant or Right [Line Items] |
|
|
| Warrants Outstanding |
884,044
|
975,335
|
| Series B Preferred Stock Warrants [Member] |
|
|
| Class of Warrant or Right [Line Items] |
|
|
| Warrants Outstanding |
10,414
|
10,414
|
| Warrants Outstanding, Exercise Price |
$ 7.4500
|
|
| Warrants Outstanding, Expiration Description |
July 31, 2018
|
|
| Series B-1 Preferred Stock Warrants, Expiration June 30, 2018 [Member] |
|
|
| Class of Warrant or Right [Line Items] |
|
|
| Warrants Outstanding |
43,969
|
47,060
|
| Warrants Outstanding, Exercise Price |
$ 7.4500
|
|
| Warrants Outstanding, Expiration Description |
June 30, 2018
|
|
| Series B-1 Preferred Stock Warrants, Expiration Various Dates In 2016 - 2021 [Member] |
|
|
| Class of Warrant or Right [Line Items] |
|
|
| Warrants Outstanding |
663,343
|
746,295
|
| Warrants Outstanding, Exercise Price |
$ 2.6075
|
|
| Warrants Outstanding, Expiration Description |
Various dates in 2016 - 2021
|
|
| Series C Preferred Stock Warrants [Member] |
|
|
| Class of Warrant or Right [Line Items] |
|
|
| Warrants Outstanding |
166,318
|
171,566
|
| Warrants Outstanding, Exercise Price |
$ 5.2150
|
|
| Warrants Outstanding, Expiration Description |
Various dates in 2022 - 2023
|
|