Operating Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Extension renewal term	5 years
Lease termination period	1 year
Operating lease right-of-use assets (Note 5)	$ 19,662	$ 21,000
Operating lease liabilities - current	8,131
Operating lease liabilities - noncurrent	10,971	$ 21,000
Total operating lease liabilities	19,102
Cash paid for amounts included in the measurement of operating lease liabilities	2,498
Operating lease right-of-use assets obtained in exchange for lease obligations	$ 60
Weighted average remaining lease term (in years)	3 years
Weighted average discount rate	7.00%
Minimum
Lessee, Lease, Description [Line Items]
Operating lease term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease term	6 years