Balance Sheets (Parenthetical) - $ / shares |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Statement Of Financial Position [Abstract] | ||
| Preferred stock, par value | $ 0.01 | $ 0.01 |
| Preferred stock, shares authorized | 5,000,000 | 5,000,000 |
| Preferred stock, shares issued | 0 | 0 |
| Preferred stock, shares outstanding | 0 | 0 |
| Common stock, par value | $ 0.01 | $ 0.01 |
| Common stock, shares authorized | 160,000,000 | 160,000,000 |
| Common stock, shares issued | 11,052,000 | 9,154,000 |
| Common stock, shares outstanding | 11,052,000 | 9,154,000 |