Quarterly Results of Operations - Schedule of Selected Financial Data for Each Quarter (Detail) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Quarterly Financial Information Disclosure [Abstract] | |||||||||||
| Revenues | $ 79 | $ 7 | $ 2,440 | $ 874 | $ 489 | $ 86 | $ 3,803 | $ 3,177 | |||
| Net loss - Basic and Diluted | $ (21,971) | $ (11,542) | $ (13,075) | $ (10,692) | $ (9,530) | $ (4,787) | $ (5,684) | $ (4,689) | $ (57,280) | $ (24,690) | $ (17,745) |
| Loss per share - Basic and Diluted | $ (0.81) | $ (0.42) | $ (0.48) | $ (0.39) | $ (0.35) | $ (0.19) | $ (0.25) | $ (0.21) | $ (2.10) | $ (1.00) | $ (0.85) |