STOCK PLANS (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-Based Compensation
Stock-based compensation expense	$ 7,047	$ 7,345	$ 15,432	$ 14,744
Compensation expense from stock options, employees	4,827	5,741	11,182	11,658
Compensation expense from stock options, non-employee awards	202	29	241	83
Restricted Stock or Unit Expense	1,819	1,389	3,609	2,611
Compensation expense from employee stock purchase plan	199	186	400	392
Stock-based compensation	7,047	7,345	$ 15,432	14,744
Purchase price of common stock, ESPP (as a percent)			85.00%
Shares issued under employee stock purchase plan (shares)			34,985
Cost of goods sold
Share-Based Compensation
Stock-based compensation expense	1,046	1,395	$ 2,252	2,770
Research and development
Share-Based Compensation
Stock-based compensation expense	951	647	1,648	1,304
Selling, general and administrative
Share-Based Compensation
Stock-based compensation expense	$ 5,050	$ 5,303	$ 11,532	$ 10,670

Compensation expense from employee stock purchase plan

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- Definition

Compensation expense from stock options (employee and board of director awards)

+ References

No definition available.

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Compensation expense from stock options, non-employee awards

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No definition available.

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- Definition

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.

+ References

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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The noncash expense that represents the cost of restricted stock or unit distributed to employees as compensation.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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Purchase price of common stock expressed as a percentage of its fair value.

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No definition available.

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- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

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