Note 10 - Leases - Maturities of Operating and Finance Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
2019 (excluding the three months ended March 31, 2019), operating leases	$ 6,072
2019 (excluding the three months ended March 31, 2019), finance leases	961
2020, operating leases	3,483
2020, finance leases	552
2021, operating leases	3,212
2021, finance leases	11
2022, operating leases	1,844
2022, finance leases
Total lease payments, operating leases	14,611
Total lease payments, finance leases	1,524
Less: Amount representing imputed interest, operating leases	(1,170)
Less: Amount representing imputed interest, finance leases	(63)
Present value of lease liabilities, operating leases	13,441
Present value of lease liabilities, finance leases	1,461
Less: Current portion of lease liabilities, operating leases	(6,335)
Less: Current portion of lease liabilities, finance leases	(1,103)	$ (1,249)
Non-current portion of lease liabilities, operating leases	7,106
Non-current portion of lease liabilities, finance leases	$ 358