Convertible Preferred Stock Warrants - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands |
1 Months Ended |
3 Months Ended |
12 Months Ended |
|
Mar. 31, 2014 |
Mar. 31, 2014 |
Dec. 31, 2016 |
Dec. 31, 2014 |
Dec. 31, 2013 |
| Class Of Stock [Line Items] |
|
|
|
|
|
| Number of securities issued upon exercise of warrants |
158,179
|
158,179
|
|
|
|
| Remeasurement of outstanding warrants |
173,910
|
|
|
|
|
| Warrants to purchase convertible preferred stock, exercise price |
$ 5.17
|
$ 5.17
|
|
|
|
| Reclassification of warrant liability |
|
$ 2,300
|
|
|
|
| IPO [Member] |
|
|
|
|
|
| Class Of Stock [Line Items] |
|
|
|
|
|
| Warrants to purchase convertible preferred stock, exercise price |
$ 21.00
|
$ 21.00
|
|
|
|
| Reclassification of warrant liability |
|
|
|
$ 2,752
|
|
| IPO [Member] | Additional Paid-in Capital [Member] |
|
|
|
|
|
| Class Of Stock [Line Items] |
|
|
|
|
|
| Reclassification of warrant liability |
$ 2,800
|
|
|
$ 2,752
|
|
| 2012 Notes [Member] |
|
|
|
|
|
| Class Of Stock [Line Items] |
|
|
|
|
|
| Percentage of shares issuable on conversion of debt as warrants |
|
|
20.00%
|
|
|
| Warrants term |
|
|
5 years
|
|
|
| Warrants expiration date |
|
|
Oct. 12, 2017
|
|
|
| Fair value of warrants |
|
|
$ 433
|
|
$ 474
|
| Risk-free interest rate |
|
|
0.21%
|
|
|
| Expected volatility |
|
|
90.00%
|
|
|
| Expected term (in years) |
|
|
1 year 6 months
|
|
|