CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares |
Mar. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Statement of Financial Position [Abstract] | ||
| Common stock, par value (usd per share) | $ 0.001 | $ 0.001 |
| Common stock, shares authorized (in shares) | 150,000,000 | 150,000,000 |
| Common stock, shares outstanding (in shares) | 62,000,000 | 60,000,000 |
| Preferred stock, par value (usd per share) | $ 0.001 | $ 0.001 |
| Preferred stock, shares authorized (in shares) | 20,000,000 | 20,000,000 |
| Preferred stock, shares issued (in shares) | 0 | 0 |
| Preferred stock, shares outstanding (in shares) | 0 | 0 |