Stock Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	May 31, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Stock compensation
Stock-based compensation expense		$ 3,600	$ 3,300	$ 12,100	$ 8,300
Weighted-average period over which remaining unrecognized compensation cost will be recognized				2 years 6 months
Number of Options
Outstanding at the beginning of period (in shares)				2,662,862
Granted (in shares)				611,250
Forfeited or expired (vested and unvested) (in shares)				(88,168)
Exercised (in shares)				(27,757)
Outstanding at the end of the period (in shares)		3,158,187		3,158,187		2,662,862
Weighted-Average Exercise Price Per Share
Outstanding at the beginning of period (in dollars per share)				$ 32.42
Granted (in dollars per share)				15.89
Forfeited or expired (vested and unvested) (in dollars per share)				29.94
Exercised (in dollars per share)				1.61
Outstanding at the end of the period (in dollars per share)		$ 29.56		$ 29.56		$ 32.42
Weighted-Average Remaining Contractual Term (Years)
Outstanding at the end of the period				7 years 10 months 28 days		8 years 4 months 10 days
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars)		$ 6,218		$ 6,218		$ 16,433
Information about the stock option plan
Number of Options, vested and expected to vest (in shares)		3,057,211		3,057,211
Number of Options, exercisable (in shares)		1,558,436		1,558,436
Weighted-Average Price Per Share, vested and expected to vest (in dollars per share)		$ 29.39		$ 29.39
Weighted-Average Price Per Share, exercisable (in dollars per share)		$ 24.74		$ 24.74
Weighted-Average Remaining Contractual Term, vested and expected to vest				7 years 10 months 13 days
Weighted-Average Remaining Contractual Term, exercisable				7 years 29 days
Aggregate Intrinsic Value, vested and expected to vest (in dollars)		$ 6,137		$ 6,137
Aggregate Intrinsic Value, exercisable (in dollars)		4,955		4,955
Additional disclosures
Unrecognized stock-based compensation expense (in dollars)		30,600		$ 30,600
RSUs
Stock compensation
Vested (in shares)				7,187
Stock-based compensation expense		100		$ 300
Unrecognized compensation cost		$ 900		$ 900
Weighted-average period over which remaining unrecognized compensation cost will be recognized				2 years 9 months 18 days
Number of Options
Outstanding and Unvested at the beginning of period (in shares)				25,000
Granted (in shares)				3,000
Forfeited or expired (in shares)				(3,000)
Vested (in shares)				(7,187)
Outstanding and Unvested at the ending of period (in shares)		17,813		17,813		25,000
Weighted-Average Exercise Price Per Share
Outstanding and unvested (in dollars per share)				$ 57.54
Granted (in dollars per share)				15.97
Forfeited or expired (in dollars per share)				15.97
Vested (in dollars per share)				57.54
Outstanding and unvested (in dollars per share)		$ 57.54		$ 57.54		$ 57.54
Maximum | RSUs
Stock compensation
Stock-based compensation expense			$ 100		$ 100
2013 Stock Option and Incentive Plan
Stock compensation
Percentage of increase in the number of shares reserved and available for issuance	2.50%
2013 Stock Option and Incentive Plan | Maximum
Stock compensation
Shares reserved and approved for issuance	2,975,000