| Commitments and Contingencies (Tables) | 9 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Sep. 30, 2019 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Commitments And Contingencies Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Maturity of Company's Operating Lease Liabilities | The maturity of the Company’s operating lease liabilities as of September 30, 2019 is as follows (in thousands): 
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| Future Undiscounted Lease Payments Under Operating Leases | The Company’s future undiscounted lease payments under operating leases (as defined by prior guidance) as of December 31, 2018 are as follow (in thousands): 
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| Supplemental Disclosure for Statement of Cash Flows and Additional Information Related to Operating Leases | The following information represents supplemental disclosure for the statement of cash flows related to operating leases (in thousands): 
 The following summarizes additional information related to operating leases (in thousands): 
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| Future Cash Flows to be Received from Subleases | The Company’s future cash flows to be received from subleases as of September 30, 2019 and December 31, 2018 is as follows (in thousands): 
 
 
 
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