Equity-Based Compensation - Activity Related to Plans (Details) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended
	Mar. 31, 2018 shares	Jun. 30, 2018 USD ($) shares	Jun. 30, 2018 USD ($) plan shares
Equity compensation plans
Number of equity compensation plans | plan			3
Stock Options
Outstanding (in shares)			3,531,359
Granted (in shares)			767,005
Exercised (in shares)			(74,006)
Expired or terminated (in shares)			(331,384)
Outstanding (in shares)		3,892,974	3,892,974
Restricted Stock Units
Restricted Stock Units
Outstanding (in shares)			1,069,775
Granted (in shares)			772,545
Vested (in shares)			(345,782)
Expired or terminated (in shares)			(81,553)
Outstanding (in shares)		1,414,985	1,414,985
2007 Equity Plan
Equity compensation plans
Increase in stock available for issuance		1,043,000
Stock Options
Outstanding (in shares)			2,590,373
Granted (in shares)			669,212
Exercised (in shares)			(71,631)
Expired or terminated (in shares)			(237,948)
Outstanding (in shares)		2,950,006	2,950,006
2007 Equity Plan | Restricted Stock Units
Restricted Stock Units
Outstanding (in shares)			966,623
Granted (in shares)			742,527
Vested (in shares)			(319,367)
Expired or terminated (in shares)			(81,093)
Outstanding (in shares)		1,308,690	1,308,690
2007 Equity Plan | Performance Restricted Stock Units (RSUs)
Restricted Stock Units
Granted (in shares)	206,250
Award vesting period			3 years
Maximum shares that may be issued		206,250	206,250
Fair value, performance- based RSUs | $		$ 3.8	$ 3.8
Compensation expense, period for recognition			3 years
2015 ESPP
Equity compensation plans
Increase in stock available for issuance		500,000
2013 Lumara Equity Plan
Stock Options
Outstanding (in shares)			125,536
Granted (in shares)			35,400
Exercised (in shares)			(2,375)
Expired or terminated (in shares)			(19,061)
Outstanding (in shares)		139,500	139,500
2013 Lumara Equity Plan | Restricted Stock Units
Restricted Stock Units
Outstanding (in shares)			11,611
Granted (in shares)			1,600
Vested (in shares)			(10,150)
Expired or terminated (in shares)			(460)
Outstanding (in shares)		2,601	2,601
Inducement Grants
Stock Options
Outstanding (in shares)			815,450
Granted (in shares)			62,393
Exercised (in shares)			0
Expired or terminated (in shares)			(74,375)
Outstanding (in shares)		803,468	803,468
Inducement Grants | Restricted Stock Units
Restricted Stock Units
Outstanding (in shares)			91,541
Granted (in shares)			28,418
Vested (in shares)			(16,265)
Expired or terminated (in shares)			0
Outstanding (in shares)		103,694	103,694