Restructuring Liabilities - Narrative (Details) ft² in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Feb. 28, 2017 position facility	Mar. 31, 2015 ft² lease	Sep. 30, 2014 facility	Dec. 31, 2003	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Research and Development Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve					$ 3,727,000	$ 0
Restructuring and related cost, number of facilities expected to close | facility	1
Restructuring and related cost, number of positions eliminated | position	70
Kendall Restructuring
Restructuring Cost and Reserve [Line Items]
Lease term (in years)				15 years
Restructuring and related activities, leased office space, maximum percentage used - not more than				50.00%
Fan Pier Move Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve					1,995,000	$ 3,626,000	$ 5,449,000	$ 5,964,000
Number of facilities decommissioned | facility			3
Number of leases terminated | lease		2
Area of real estate property (in square feet) | ft²		120
Discount rate related to leases (percent)		9.00%
Other Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve					0		$ 1,262,000	$ 1,450,000
Employee Severance | Research and Development Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost					6,800,000
Asset Impairments | Research and Development Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost					2,000,000
Minimum | Research and Development Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost					11,300,000
Minimum | Facility Closing | Research and Development Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost					2,500,000
Maximum | Research and Development Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost					13,000,000
Maximum | Facility Closing | Research and Development Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost					$ 4,200,000