OTHER ASSETS (Tables)

12 Months Ended

Dec. 31, 2017

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, 2017		As of December 31, 2016
	(in thousands)
Manufacturing-related deposits and prepaids	$	18,650	$	23,604
Prepaid clinical and preclinical expenses		5,175		1,225
Prepaid research expenses		2,896		—
Prepaid maintenance services		1,711		109
Prepaid commercial expenses		1,589		54
Asset held for sale		1,501		—
Other prepaids		2,726		989
Other		2,263		914
Total other current assets	$	36,511	$	26,895

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, 2017		As of December 31, 2016
	(in thousands)
Long-term available-for-sale securities	$	9,980	$	—
Prepaid clinical expenses		7,488		3,725
Alternative minimum tax credit		3,315		—
Restricted cash and investments		784		784
Other		242		242
Total investments and other assets	$	21,809	$	4,751