STOCK-BASED COMPENSATION - Narrative (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 10,596,000	$ 12,585,000	$ 13,016,000
Tax benefit on total stock-based compensation	600,000	700,000	$ 400,000
Cash received from stock option exercises		$ 1,500,000
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 9,200,000
Average vesting period for recognition of unrecognized compensation expense	1 year 9 months 11 days
Performance-based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 4,400,000
Average vesting period for recognition of unrecognized compensation expense	1 year 8 months 16 days
Weighted-average grant date fair value of stock purchase rights granted (in dollars per share)	$ 6.87
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense	$ 1,100,000
Average vesting period for recognition of unrecognized compensation expense	1 year 3 months 26 days
Weighted-average grant date fair value of awards granted (in dollars per share)		$ 4.32	$ 5.55
Total intrinsic value of options exercised		$ 600,000	$ 5,000,000
Cash received from stock option exercises		1,500,000	7,000,000
Total fair value of options vested	$ 1,400,000	$ 2,300,000	$ 4,700,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of stock purchase rights granted (in dollars per share)	$ 1.15	$ 1.73	$ 2.97
Inventory
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 0	$ 0	$ 0

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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