CONVERTIBLE REDEEMABLE PREFERRED STOCK - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Increase (decrease) in convertible redeemable preferred stock
Accruals of dividends and accretion to redemption value	$ 31,184
Conversion of preferred stock to common stock	$ 119,250
Balance at end of year (in shares)	0
Series A convertible redeemable preferred stock
Increase (decrease) in convertible redeemable preferred stock
Balance at beginning of year	$ 12,781	$ 12,277	$ 23,546
Balance at beginning of year (in shares)	9,232,334	9,232,334	18,464,674
Accruals of dividends and accretion to redemption value	$ 2,297	$ 504	$ 970
Conversion of preferred stock to common stock	$ (11,345)
Conversion of preferred stock to common stock (in shares)	(9,232,334)
Extinguishment of prior preferred stock dividends	$ (3,733)
Performance Adjustment			$ (12,239)
Performance Adjustment of (in shares)			(9,232,340)
Balance at end of year		$ 12,781	$ 12,277
Balance at end of year (in shares)	0	9,232,334	9,232,334
Series B convertible redeemable preferred stock
Increase (decrease) in convertible redeemable preferred stock
Balance at beginning of year	$ 51,212	$ 49,376	$ 47,540
Balance at beginning of year (in shares)	27,324,237	27,324,237	27,324,237
Accruals of dividends and accretion to redemption value	$ 18,034	$ 1,836	$ 1,836
Conversion of preferred stock to common stock	$ (45,905)
Conversion of preferred stock to common stock (in shares)	(27,324,237)
Extinguishment of prior preferred stock dividends	$ (23,341)
Balance at end of year		$ 51,212	$ 49,376
Balance at end of year (in shares)	0	27,324,237	27,324,237
Series C convertible redeemable preferred stock
Increase (decrease) in convertible redeemable preferred stock
Balance at beginning of year	$ 13,114
Balance at beginning of year (in shares)	8,658,008	8,658,008
Issuance of new convertible redeemable preferred stock, net of issuance costs			$ 12,034
Issuance of new redeemable preferred stock (in shares)			12,154,000
Accruals of dividends and accretion to redemption value	$ 2,996	$ 960	$ 120
Conversion of preferred stock to common stock	$ (12,000)
Conversion of preferred stock to common stock (in shares)	(8,658,008)
Extinguishment of prior preferred stock dividends	$ (4,110)
Balance at end of year		$ 13,114
Balance at end of year (in shares)	0	8,658,008	8,658,008
Series D convertible redeemable preferred stock
Increase (decrease) in convertible redeemable preferred stock
Issuance of new convertible redeemable preferred stock, net of issuance costs	$ 44,807
Issuance of new redeemable preferred stock (in shares)	37,500,000
Accruals of dividends and accretion to redemption value	$ 1,245
Conversion of notes to preferred stock	$ 5,000
Conversion of notes to preferred stock (in shares)	4,166,667
Conversion of preferred stock to common stock	$ (50,000)
Conversion of preferred stock to common stock (in shares)	(41,666,667)
Extinguishment of prior preferred stock dividends	$ (1,052)