Description of Business - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands |
1 Months Ended | 3 Months Ended | 6 Months Ended | 16 Months Ended | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Feb. 13, 2017 |
Aug. 31, 2018 |
Feb. 28, 2018 |
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Dec. 31, 2017 |
Mar. 31, 2017 |
Dec. 31, 2016 |
|
Description of Business [Line Items] | |||||||||||
Accumulated deficit | $ (106,968) | $ (106,968) | $ (106,968) | $ (93,593) | |||||||
Net loss | $ (8,714) | $ (7,312) | (13,375) | $ (14,292) | |||||||
Proceeds from the sale of common stock | $ 40,700 | $ 2,700 | 10,200 | ||||||||
Aggregate offering price | $ 50,000 | ||||||||||
Shares sold (in shares) | 372,852 | 1,213,386 | |||||||||
Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 | $ 0.01 | $ 0.01 | |||||||
Weighted-average share price (in usd per share) | $ 7.37 | $ 8.74 | |||||||||
Cash and cash equivalents | $ 43,402 | $ 43,402 | $ 43,402 | $ 47,441 | $ 46,335 | $ 22,104 | |||||
Short-term investments | $ 32,860 | $ 32,860 | $ 32,860 | $ 0 | |||||||
Underwriting Agreement | |||||||||||
Description of Business [Line Items] | |||||||||||
Sale price (in usd per share) | $ 5.50 | ||||||||||
Underwriter Option | |||||||||||
Description of Business [Line Items] | |||||||||||
Proceeds from the sale of common stock | $ 37,900 | ||||||||||
Shares sold (in shares) | 7,414,996 | ||||||||||
Subsequent Event | LLS | |||||||||||
Description of Business [Line Items] | |||||||||||
Aggregate offering price | $ 5,000 | ||||||||||
Shares sold (in shares) | 150,987 | ||||||||||
Sale price (in usd per share) | $ 6.62 |