Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2020

Accounting Policies [Abstract]

Schedule of Revenue Disaggregated by Geographic Region

The nature, amount, timing, and uncertainty of our revenue and how revenue and cash flows are affected by economic factors is most appropriately depicted by geographic region (using the location of the client as the basis of attributing revenue to the individual regions) as follows (in thousands):

	Quarter Ended				Six Months Ended
	June 30,				June 30,
	2020		2019		2020		2019
Americas (principally the U.S.)	$	209,926	$	214,390	$	426,923	$	425,120
Europe, Middle East, and Africa		22,134		22,606		43,166		47,232
Asia Pacific		8,261		8,860		15,849		18,297
Total revenue	$	240,321	$	245,856	$	485,938	$	490,649

Fair Value Measurements

The following table represents the fair value hierarchy based upon three levels of inputs, of which Levels 1 and 2 are considered observable and Level 3 is unobservable, for our financial assets measured at fair value (in thousands):

	June 30, 2020						December 31, 2019
	Level 1		Level 2		Total		Level 1		Level 2		Total
Cash equivalents:
Money market funds	$	29,240	$	—	$	29,240	$	4,847	$	—	$	4,847
Commercial paper		—		5,797		5,797		—		26,964		26,964
Short-term investments:
Corporate debt securities		—		24,090		24,090		—		22,159		22,159
Asset-backed securities		—		3,093		3,093		—		3,950		3,950
Total	$	29,240	$	32,980	$	62,220	$	4,847	$	53,073	$	57,920

Carrying Value (Par Value for Convertible Debt) and Estimated Fair Value of Debt

We have chosen not to measure our debt at fair value, with changes recognized in earnings each reporting period.  The following table indicates the carrying value (par value for convertible debt) and estimated fair value of our debt as of the indicated periods (in thousands):

	June 30, 2020				December 31, 2019
	Carrying		Fair		Carrying		Fair
	Value		Value		Value		Value
2018 Credit Agreement (carrying value including current maturities)	$	132,188	$	132,188	$	136,875	$	136,875
2016 Convertible debt (par value)		230,000		238,625		230,000		262,775