Cash and Cash Equivalents and Short Term Investments (Tables)

12 Months Ended

Dec. 31, 2017

Cash And Cash Equivalents [Abstract]

Summary of Cash and Cash Equivalents

a. Cash and cash equivalents:

Cash equivalents include items almost as liquid as cash, such as certificates of deposit and time deposits with maturity periods of three months or less when purchased.

	December 31,
	2017		2016
Cash	$	5,522	$	29,915
Money market funds		73,070		69,865
Total cash and cash equivalents	$	78,592	$	99,780