Net Loss Per Share - Additional Information (Detail) - shares |
3 Months Ended | |
---|---|---|
Mar. 31, 2019 |
Mar. 31, 2018 |
|
Stock Option [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Common stock excluded from the calculation of weighted average shares for diluted net loss per share | 6,774,000 | 4,705,000 |
Warrants [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Common stock excluded from the calculation of weighted average shares for diluted net loss per share | 22,216,000 | 9,626,000 |