REDEEMABLE CONVERTIBLE PREFERRED STOCK (Tables)

9 Months Ended

Sep. 30, 2018

Temporary Equity Disclosure [Abstract]

Summary of the change in carrying amount of the outstanding redeemable convertible preferred stock

A summary of the change in carrying amount of the outstanding redeemable convertible preferred stock is as follows (in thousands):

	Series G’ Stock					Series G Stock
	Shares		Amount			Shares		Amount
Balance — December 31, 2017	1,296		$	44,672		346		$	5,110
Accretion of redeemable convertible preferred stock	—		—			—		108
Conversion of preferred stock to common stock	(1,296	)	(44,672		)	(346	)	(5,218		)
Balance — September 30, 2018	—		$	—		—		$	—

	Series F-R Stock					Series E-R Stock					Series D-R Stock
	Shares		Amount			Shares		Amount			Shares		Amount
Balance — December 31, 2017	1,199		$	58,449		795		$	29,972		1,396		$	32,728
Accretion of redeemable convertible preferred stock	—		38			—		1			—		7
Conversion of preferred stock to common stock	(1,199	)	(58,487		)	(795	)	(29,973		)	(1,396	)	(32,735		)
Balance — September 30, 2018	—		$	—		—		$	—		—		$	—

	Series C-R Stock					Series B-R Stock					Series A-R Stock
	Shares		Amount			Shares		Amount			Shares		Amount
Balance — December 31, 2017	1,508		$	18,366		2,247		$	5,288		1,857		$	1,852
Accretion of redeemable convertible preferred stock	—		3			—		—			—		—
Conversion of preferred stock to common stock	(1,508	)	(18,369		)	(2,247	)	(5,288		)	(1,857	)	(1,852		)
Balance — September 30, 2018	—		$	—		—		$	—		—		$	—