Restructuring Charge (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Feb. 28, 2018 employee	Jun. 30, 2019 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($) ft²	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Restructuring
Severance costs, charges incurred						$ 2,300
Restructuring charge
Restructuring charge							$ 1,487	$ 21,433	$ 3,693
Workforce reduction
Restructuring charge
Balance at beginning of the period							4,087
Additional charges/adjustments during the period				$ 15,300			(116)
Payments during the period							(3,187)
Balance at end of the period							$ 784	4,087
Workforce reduction | 2019 Corporate Restructuring
Restructuring
Charge for severance related to a pre-existing plan		$ 16,000
Workforce reduction | 2018 Manufacturing Restructuring
Restructuring
Number of employees eliminated due to new operating model | employee	22
Workforce reduction | 2018 Manufacturing Restructuring | Stock options
Restructuring
Severance costs, charges incurred			$ 200
Workforce reduction | 2016 Corporate Restructuring
Restructuring charge
Unoccupied office space for sub-lease | ft²							10,281
Lease | 2016 Corporate Restructuring
Restructuring charge
Leasehold impairment charge								600
One-time charge | 2018 Manufacturing Restructuring
Restructuring
Severance costs, charges incurred			$ 1,200
Incremental retention benefits | 2019 Corporate Restructuring
Restructuring
Severance costs, charges incurred		4,000					$ 1,600	$ 2,400
Winter Street 930 Waltham MA
Restructuring charge
Unoccupied office space for sub-lease | ft²							10,281
Leasehold impairment charge					$ 600
Winter Street 930 Waltham MA | Lease | 2019 Corporate Restructuring
Restructuring charge
Impairment charge to write down excess equipment to fair value		$ 2,500