Property and Equipment - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands |
Jun. 30, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|---|---|---|---|
| Property Plant And Equipment [Line Items] | |||
| Property and equipment, gross | $ 2,631 | $ 2,610 | $ 2,364 |
| Less: accumulated depreciation and amortization | (2,085) | (1,896) | (1,534) |
| Property and equipment, net | 546 | 714 | 830 |
| Machinery and Equipment [Member] | |||
| Property Plant And Equipment [Line Items] | |||
| Property and equipment, gross | 1,361 | 1,357 | 1,170 |
| Computer Equipment [Member] | |||
| Property Plant And Equipment [Line Items] | |||
| Property and equipment, gross | 305 | 294 | 246 |
| Office Equipment [Member] | |||
| Property Plant And Equipment [Line Items] | |||
| Property and equipment, gross | 203 | 203 | 203 |
| Leasehold Improvements [Member] | |||
| Property Plant And Equipment [Line Items] | |||
| Property and equipment, gross | 756 | $ 756 | $ 745 |
| Construction in Progress [Member] | |||
| Property Plant And Equipment [Line Items] | |||
| Property and equipment, gross | $ 6 |