Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Apr. 02, 2014	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018	Sep. 30, 2012
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Restricted cash		$ 1,300		$ 1,300			$ 1,700
Right-of-use asset		10,308		10,308		$ 11,800
Lease liability		10,669		10,669
Stock-based compensation expense in operating income		1,712	$ 2,084	5,031	$ 5,524
Operating Expenses | Incentive-Based Compensation Plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense in operating income		900	$ 1,900	2,200	$ 4,400
NWHW Holdings
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Percentage of full diluted equity								20.00%
Carrying value of investment		5,200		5,200			6,700
Second Avenue Software, Inc.
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Percentage of full diluted equity	26.00%
Carrying value of investment		$ 800		$ 800			$ 800
Payments to acquire investments	$ 1,500
ASU 2016-02
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Right-of-use asset						12,100
Lease liability						$ 12,100