Related Party - Additional Information (Detail) - Amunix Inc. [Member] - USD ($) $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Related Party Transaction [Line Items] | ||||
| Additional consideration, milestone payments | $ 30.0 | |||
| Operating expenses from related party transaction | $ 0.6 | $ 0.8 | $ 0.8 | |
| Due to related party | $ 0.1 | $ 0.1 | ||
| Preferred stock [Member] | ||||
| Related Party Transaction [Line Items] | ||||
| Ownership percentage | 10.00% | |||
| Common Stock [Member] | Maximum [Member] | ||||
| Related Party Transaction [Line Items] | ||||
| Ownership percentage | 5.00% | |||