ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018 USD ($) region	Dec. 31, 2017 USD ($)
Cash and Cash Equivalents [Abstract]
Number of regions in which company sells products | region	3
Credit card receivables	$ 2,700	$ 2,000
Cash and cash equivalents held in foreign bank accounts	33,800	30,600
Restricted Cash [Abstract]
Restricted cash	9,100	9,100
Accounts Receivable [Abstract]
Accounts receivable, net of allowance	400	273
Allowance for doubtful accounts	600	600
Other Assets [Abstract]
Other assets	3,944	3,876
Deposits for building leases	2,000	1,900
Fair trade commission deposits	1,800	1,700
Indefinite lived intangible assets	200	200
Notes Payable [Abstract]
Notes payable	900	800
Notes payable, current portion	916	815
Other Long-Term Liabilities [Abstract]
Other long-term liabilities	2,850	1,265
Uncertain income tax position	200	200
Accrued lease restoration costs	400	400
Defined benefit plan obligation	395	400
Lease incentive payable, noncurrent	$ 1,400
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
Valuation and Qualifying Accounts Disclosure [Line Items]
Deferred commissions	$ 3,912	3,880
Amortization of deferred commissions	2,700
Deferred revenue	8,605	8,561
Deferred revenue, revenue recognized during the period	6,800
Loyalty Program [Roll Forward]
Loyalty deferred revenue, beginning balance	6,406	7,033
Loyalty points forfeited or expired	(1,235)	(5,895)
Loyalty points used	(3,565)	(14,316)
Loyalty points vested	2,808	17,836
Loyalty points unvested	1,725	1,748
Loyalty deferred revenue, ending balance	6,139	6,406
Reserve for Sales Returns
Movement in Valuation Allowances and Reserves [Roll Forward]
Provision related to sales made in current period	340
Adjustment related to sales made in prior periods	(24)
Actual returns or credits related to current period	(220)
Actual returns or credits related to prior periods	(93)
Sales reserve, end of period	$ 120	$ 117