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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- Definition

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.

+ References

No definition available.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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- Definition

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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- Definition

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

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- Definition

The number of grants made 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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- Definition

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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STOCK-BASED COMPENSATION - Schedule of Stock Based Compensation Expense Recognized (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Stock-based compensation
Total	$ 2,634	$ 5,270	$ 5,336	$ 7,504
Stock Options
Stock-based compensation
Total unrecognized compensation expense	1,800		$ 1,800
Average vesting period for recognition of unrecognized compensation expense			2 years 2 months 1 day
Restricted Stock Units and Performance-based Restricted Stock Units
Stock-based compensation
Average vesting period for recognition of unrecognized compensation expense			2 years 6 months 15 days
Total unrecognized compensation expense	21,000		$ 21,000
Restricted Stock Units
Stock-based compensation
Award granted (in shares)			2.2
Granted (in dollars per share)			$ 4.36
Performance-based Restricted Stock Units
Stock-based compensation
Award granted (in shares)			0.6
Granted (in dollars per share)			$ 6.87
Cost of sales
Stock-based compensation
Total	50	16	$ 50	30
Research and development expense
Stock-based compensation
Total	76	14	349	67
Selling, general and administrative expense
Stock-based compensation
Total	2,508	2,940	4,937	4,849
Restructuring
Stock-based compensation
Total	$ 0	$ 2,300	$ 0	$ 2,558