Financial Instruments

12 Months Ended

Dec. 31, 2018

Cash and Cash Equivalents [Abstract]

Financial Instruments

Financial Instruments

Cash, Cash Equivalents and Restricted Cash

The carrying value of cash and cash equivalents approximate fair value and are as follows (in thousands):

	December 31,
	2018		2017
As held
Cash	$	136,642	$	101,356
Money market funds	143,843		79,256
	$	280,485	$	180,612
As reported
Cash and cash equivalents	$	220,728	$	103,828
Restricted cash	59,757		76,784
	$	280,485	$	180,612

Restricted cash consisted of the following (in thousands):

	December 31,
	2018		2017
Current
Restricted cash	$	25,740	$	36,418
Restricted cash related to PPA Entities	2,917		7,969
Restricted cash, current	$	28,657	$	44,387
Non-current
Restricted cash	$	3,246	$	5,649
Restricted cash related to PPA Entities	27,854		26,748
Restricted cash, non-current	31,100		32,397
	$	59,757	$	76,784

Short-Term Investments

As of December 31, 2018 and 2017, the Company had short-term investments in U.S. Treasury Bills of $104.4 million and $26.8 million, respectively.

Derivative Instruments

The Company has derivative financial instruments related to natural gas forward contracts and interest rate swaps. See Note 7 - Derivative Financial Instrumentsfor a full description of the Company's derivative financial instruments.