FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Schedule of fair value on a recurring basis

The following table presents the Company’s asset and liabilities that are measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of December 31, 2015 (in thousands):

	As of December, 2015		Fair Value Hierarchy at December 31, 2015
	Total carrying and estimated fair value		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Asset:
Marketable securities, available-for-sale	$	191,799	$	—	$	191,799	$	—
Liabilities:
Derivative liability related to warrants	$	38,810	$	—	$	—	$	38,810
Business combination-related contingent consideration	$	59,021	$	—	$	—	$	59,021

The following table presents the Company’s asset and liabilities that are measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of December 31, 2014 (in thousands):

	As of December, 2014		Fair Value Hierarchy at December 31, 2014
	Total carrying and estimated fair value		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Asset:
Marketable securities, available-for-sale	$	9,556	$	9,556	$	—	$	—
Liabilities:
Derivative liability related to warrants	$	27,990	$	—	$	—	$	27,990
Business combination-related contingent consideration	$	11,637	$	—	$	—	$	11,637

Schedule of fair value measurements of common stock warrants using significant unobservable inputs (Level 3)

The following table sets forth a summary of changes in the estimated fair value of the Company’s Level 3 derivative liability for the period from January 1, 2015 through December 31, 2015:

	Fair Value Measurements of Common Stock Warrants Using Significant  Unobservable Inputs (Level 3)
Balance at January 1, 2015	$	27,990
Issuance of common stock warrants	1,050
Reclassification of derivative liability to equity upon exercise of warrants	(23,537		)
Change in estimated fair value of liability classified warrants	33,307
Balance at December 31, 2015	$	38,810

The following table sets forth a summary of changes in the estimated fair value of the Company’s Level 3 derivative liability for the period from January 1, 2014 through December 31, 2014:

	Fair Value Measurements of Common Stock Warrants Using Significant Unobservable Inputs (Level 3)
Balance at January 1, 2014	$	25,037
Issuance of common stock warrants	2,531
Reclassification of derivative liability to equity upon exercise of warrants	(23,364		)
Change in estimated fair value of liability classified warrants	23,786
Balance at December 31, 2014	$	27,990

Schedule of fair value measurements of acquisition-related contingent consideration

The following table sets forth a summary of changes in the estimated business combination-related contingent consideration for the period from January 1, 2015 through December 31, 2015:

	Fair Value Measurements of Acquisition-Related Contingent Consideration (Level 3)
Balance at January 1, 2015	$	11,637
Present value of contingent consideration related to Cholbam acquisition, upon acquisition	39,107
Increase from revaluation of contingent consideration	13,778
Decrease of contingent consideration, asset divestiture	(604		)
Contractual Payments	(3,938		)
Contractual Payments accrued at December 31, 2015	(959		)
Balance at December 31, 2015	$	59,021

The following table sets forth a summary of changes in the estimated acquisition-related contingent consideration for the period from January 1, 2014 through December 31, 2014:

	Fair Value Measurements of Acquisition-Related Contingent Consideration
Balance at January 1, 2014	$	—
Present value of contingent consideration related to Manchester acquisition, upon acquisition	12,800
Contractual Payments	(1,163		)
Balance at December 31, 2014	$	11,637