Stock-Based Compensation Expense - Stock Option Awards Outstanding Rollforward (Details) - $ / shares		12 Months Ended
	Sep. 26, 2016	Dec. 31, 2016
Number of Stock Option Awards Outstanding
Stock option awards outstanding at the beginning of the year (in shares)		7,006,472
Stock option awards granted (in shares)		325,000
Stock option awards forfeited (in shares)		(738,273)
Stock option awards exercised (in shares)		(167,367)
Stock option awards outstanding at the end of the year (in shares)		6,425,832
Stock option awards vested and exercisable at the end of the year (in shares)		5,107,030
Weighted Average Exercise Price Per Share
Stock option awards outstanding at the beginning of the year (in dollars per share)		$ 3.79
Stock option awards granted (in dollars per share)		1.69
Stock option awards forfeited (in dollars per share)		4.68
Stock option awards exercised (in dollars per share)		0.96
Stock option awards outstanding at the end of the year (in dollars per share)		3.65
Stock option awards vested and exercisable at the end of the year (in dollars per share)		$ 3.96
Stock option awards
Stock-Based Compensation
Cliff period		1 year
Stock option awards | Maximum
Stock-Based Compensation
Vesting period		4 years
Expiration period		10 years
CMO
Number of Stock Option Awards Outstanding
Stock option awards granted (in shares)	125,000
Weighted Average Exercise Price Per Share
Stock option awards granted (in dollars per share)	$ 1.59