SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENT ACCOUNTING PRONOUNCEMENTS (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Summary of Components of Inventory

The following table summarizes the components of the Company’s inventory for each of the periods indicated:

	As of December 31, 2017		As of December 31, 2016
	(in thousands)
Raw materials	$	53,875	$	9,531
Work in progress		27,442		3,175
Finished goods		2,288		107
Total inventory	$	83,605	$	12,813

Summary of Estimated Useful Lives of Property and Equipment

The Company generally depreciates the cost of its property and equipment using the straight-line method over the estimated useful lives of the respective assets, which are summarized as follows:

Asset Category	Useful lives
Lab equipment	5 years
Office equipment	5 years
Software and computer equipment	3 - 5 years
Leasehold improvements	Lesser of the useful life or the term of    the respective lease
Land	Not depreciated
Building	30 years
Construction in Progress	Not depreciated until put into service

Summary of Estimated Future Amortization for Intangible Assets

The following table summarizes the estimated future amortization for intangible assets for the next five years:

	As of December 31, 2017 (in thousands)
2018		1,681
2019		1,507
2020		1,465
2021		1,453
2022		1,446
Total	$	7,552