Note 4 - Balance Sheet Detail - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued payroll and related expenses	$ 12,567	$ 9,036
Sales and marketing accruals	3,710	706
Accrued sales tax	2,920	2,373
Warranty liability	3,508	2,461
Other accrued liabilities	4,143	2,821
Total	$ 26,848	$ 17,397