LEASES - Additional Information (Details)	3 Months Ended	6 Months Ended
	Jun. 29, 2019 USD ($)	Jun. 29, 2019 USD ($)
LEASES
Operating lease cost	$ 436,000	$ 831,000
Short-term lease costs	120,000	209,000
Cash paid, lease liabilities	$ 299,000	$ 619,000
Weighted-average remaining lease term	5 years 1 month 6 days	5 years 1 month 6 days
Right-of-use assets	$ 604,000	$ 604,000
Lease liabilities	$ 604,000	$ 604,000
Weighted-average discount rate	6.10%	6.10%