COMMITMENTS AND CONTINGENCIES - Contractual obligations (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Payment due by period, Contractual obligations, Less than 1 year	$ 49,499
Payment due by period, Contractual obligations, 1-3 years	33,785
Payment due by period, Contractual obligations, 3-5 years	3,709
Payment due by period, Contractual obligations, More than 5 years	10,615
Payment due by period, Contractual obligations, Total	97,608
Operating Leases [Member]
Payment due by period, Contractual obligations, Less than 1 year	2,331
Payment due by period, Contractual obligations, 1-3 years	3,785
Payment due by period, Contractual obligations, 3-5 years	3,709
Payment due by period, Contractual obligations, More than 5 years	10,615
Payment due by period, Contractual obligations, Total	20,440
Long-term debt [Member]
Payment due by period, Contractual obligations, Less than 1 year	0
Payment due by period, Contractual obligations, 1-3 years	30,000
Payment due by period, Contractual obligations, 3-5 years	0
Payment due by period, Contractual obligations, More than 5 years	0
Payment due by period, Contractual obligations, Total	30,000
Contract Manufacturer [Member]
Payment due by period, Contractual obligations, Less than 1 year	47,168
Payment due by period, Contractual obligations, 1-3 years	0
Payment due by period, Contractual obligations, 3-5 years	0
Payment due by period, Contractual obligations, More than 5 years	0
Payment due by period, Contractual obligations, Total	$ 47,168