Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands |
Jun. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Statement of Financial Position [Abstract] | ||
| Series A convertible redeemable preferred stock, par value | $ 0.0001 | $ 0.0001 |
| Series A convertible redeemable preferred stock, shares authorized | 13,000,000 | 13,000,000 |
| Series A convertible redeemable preferred stock, shares issued | 11,381,999 | 11,381,999 |
| Series A convertible redeemable preferred stock, shares outstanding | 11,381,999 | 11,381,999 |
| Series A convertible redeemable preferred stock, liquidation preference | $ 28,455 | $ 28,455 |
| Common stock, par value | $ 0.0001 | $ 0.0001 |
| Common stock, shares authorized | 50,000,000 | 50,000,000 |
| Common stock, shares issued | 10,000,000 | 10,000,000 |
| Common stock, shares outstanding | 10,000,000 | 10,000,000 |