OTHER ASSETS (Tables)

12 Months Ended

Dec. 31, 2018

Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]

Summary of Other Current Assets

The following table summarizes the Company’s other current assets for each of the periods indicated:

	As of December 31, 2018		As of December 31, 2017
	(in thousands)
Manufacturing-related deposits and prepaids	$	39,036	$	18,650
Leasehold improvement receivable		13,474		—
Prepaid clinical and pre-clinical expenses		9,706		5,175
Prepaid maintenance services		2,994		1,711
Prepaid income tax		2,130		—
Prepaid research expenses		1,932		2,896
Interest receivable		1,918		709
Prepaid commercial expenses		1,573		1,589
Asset held for sale		—		1,501
Other prepaids		3,671		2,726
Other		1,348		1,554
Total other current assets	$	77,782	$	36,511

Summary of Investments and Other Assets

The following table summarizes the Company’s investments and other assets for each of the periods indicated:

	As of December 31, 2018		As of December 31, 2017
	(in thousands)
Manufacturing-related deposits	$	62,821	$	—
Strategic investments		31,739		—
Prepaid clinical expenses		7,541		7,488
Alternative minimum tax credit		3,367		3,315
Restricted investments		1,001		784
Long-term available-for-sale securities		—	$	9,980
Other		825		242
Total investments and other assets	$	107,294	$	21,809