Stock-Based Compensation - Stock Option Awards Outstanding Rollforward (Details) - $ / shares		12 Months Ended
	Jul. 10, 2017	Dec. 31, 2017
Number of Stock Option Awards Outstanding
Stock option awards outstanding, beginning of year (shares)		6,425,832
Stock option awards granted (shares)		1,100,000
Stock option awards forfeited (shares)		(775,388)
Stock option awards exercised (shares)		(439,385)
Stock option awards outstanding, end of year (shares)		6,311,059
Stock option awards vested and exercisable (shares)		5,100,068
Weighted Average Exercise Price Per Share
Stock option awards outstanding, beginning of year (usd per share)		$ 3.65
Stock option awards granted (usd per share)		2.39
Stock option awards forfeited (usd per share)		3.17
Stock option awards exercised (usd per share)		1.58
Stock option awards outstanding, end of year (usd per share)		3.63
Stock option awards vested and exercisable (usd per share)		$ 3.96
Stock option awards outside of equity compensation plan
Stock-Based Compensation
Cliff period		1 year
Stock option awards outside of equity compensation plan | Chief Executive Officer
Number of Stock Option Awards Outstanding
Stock option awards granted (shares)		450,000
Weighted Average Exercise Price Per Share
Stock option awards granted (usd per share)		$ 2.36
Stock option awards outside of equity compensation plan | Maximum
Stock-Based Compensation
Vesting period		4 years
Expiration period		10 years
Performance options award | Chief Executive Officer
Number of Stock Option Awards Outstanding
Stock option awards granted (shares)	450,000	450,000
Weighted Average Exercise Price Per Share
Stock option awards granted (usd per share)		$ 2.36