Stock-Based Compensation - Stock Option Activity (Details) - Stock Options	6 Months Ended
	Jun. 30, 2018 $ / shares shares
Stock Options
Beginning, outstanding (in shares) | shares	189,466
Granted (in shares) | shares	0
Exercised (in shares) | shares	0
Canceled (in shares) | shares	(60,243)
Forfeited (in shares) | shares	0
Ending, outstanding (in shares) | shares	129,223
Exercisable (in shares) | shares	129,223
Weighted Average Exercise Price
Beginning, outstanding (in dollars per share) | $ / shares	$ 84.81
Granted (in dollars per share) | $ / shares	0.00
Exercised (in dollars per share) | $ / shares	0.00
Canceled (in dollars per share) | $ / shares	94.37
Forfeited (in dollars per share) | $ / shares	0.00
Ending, outstanding (in dollars per share) | $ / shares	80.35
Exercisable (in dollars per share) | $ / shares	$ 80.35