Stock-based Compensation - Restricted Stock Unit Awards - Activity (Details) - Restricted Stock Unit Awards	3 Months Ended
	Mar. 31, 2017 $ / shares shares
Awards
Unvested at the beginning of the period (in shares) | shares	1,359,142
Granted (in shares) | shares	33,052
Forfeited (in shares) | shares	(7,129)
Unvested at the end of the period (in shares) | shares	1,385,065
Weighted Average Grant Date Fair Value per Share
Unvested at the beginning of the period (in dollars per share) | $ / shares	$ 5.60
Granted (in dollars per share) | $ / shares	4.60
Forfeited (in dollars per share) | $ / shares	4.60
Unvested at the end of the period (in dollars per share) | $ / shares	$ 5.58