Summary of Significant Accounting Policies - Impact of Adoption (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets	$ 4,453
Current portion of operating lease liability	2,504
Operating lease liability, net of current portion	2,770
Accrued and other liabilities	9,682		$ 12,857	[1]
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets		$ 5,810
Current portion of operating lease liability		1,892
Operating lease liability, net of current portion		4,684
Accrued and other liabilities		12,673	12,857
Other long-term liabilities			$ 582
Under Topic 840
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accrued and other liabilities	9,989
Other long-term liabilities	349
Effect of Change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets	4,453
Current portion of operating lease liability	2,504
Operating lease liability, net of current portion	2,770
Accrued and other liabilities	(307)
Other long-term liabilities	$ (349)
Effect of Change | ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets		5,810
Current portion of operating lease liability		1,892
Operating lease liability, net of current portion		4,684
Accrued and other liabilities		(184)
Other long-term liabilities		$ (582)

[1] Derived from the audited consolidated financial statements included in the Company’s Annual Report on Form 10K for the year ended December 31, 2018.