Restructuring Expenses (Details)		3 Months Ended		6 Months Ended	9 Months Ended
	Feb. 15, 2017 USD ($) Employee	Sep. 30, 2017 USD ($)	Jun. 30, 2016 Employee	Jun. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | Employee	100		36
Restructuring expected cost	$ 4,300,000
Restructuring expenses		$ 0			$ 4,300,000
Employee severance
Restructuring Cost and Reserve [Line Items]
Restructuring expected cost	3,800,000
Restructuring expenses				$ 1,700,000
Payments for restructuring					3,200,000
Facility-related cost
Restructuring Cost and Reserve [Line Items]
Restructuring expected cost	$ 500,000
Payments for restructuring					200,000
Restructuring costs incurred					600,000
Accrued severance and related expenses | Employee severance
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, unpaid balance in accrued compensation		600,000			600,000
Accrued severance and related expenses | Facility-related cost
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, unpaid balance in accrued compensation		$ 400,000			$ 400,000