Short-term investments (Tables)

6 Months Ended

Jun. 30, 2018

Cash, Cash Equivalents, and Short-term Investments [Abstract]

Schedule of Available-for-sale Securities Reconciliation

The following tables summarize unrealized gains and losses related to our short-term investments designated as available-for-sale:

	As of June 30, 2018
(In thousands)	(Unaudited)
			Gross		Gross
	Adjusted Cost		Unrealized Gain		Unrealized Loss			Fair Value
Corporate bonds	$	170,921	$	177	$	(948	)	$	170,150
U.S. treasuries and agencies	39,353		1		—			39,354
Time deposits	1,300		—		—			1,300
Total Short-term investments	$	211,574	$	178	$	(948	)	$	210,804

(In thousands)	As of December 31, 2017
			Gross		Gross
	Adjusted Cost		Unrealized Gain		Unrealized Loss			Fair Value
Corporate bonds	$	120,341	$	182	$	(395	)	$	120,128
Time deposits	1,760		—		—			1,760
Total Short-term investments	$	122,101	$	182	$	(395	)	$	121,888

Investments Classified by Contractual Maturity Date

The following tables summarize the contractual maturities of our short-term investments designated as available-for-sale:

	As of June 30, 2018
(In thousands)	(Unaudited)
	Adjusted Cost		Fair Value
Due in less than 1 year	$	112,533	$	112,405
Due in 1 to 5 years	99,041		98,399
Total available-for-sale debt securities	$	211,574	$	210,804
Due in less than 1 year	Adjusted Cost		Fair Value
Corporate bonds	$	71,880	$	71,751
U.S. treasuries and agencies	39,353		39,354
Time deposits	1,300		1,300
Total available-for-sale debt securities	$	112,533	$	112,405
Due in 1 to 5 years	Adjusted Cost		Fair Value
Corporate bonds	$	99,041	$	98,399
Total available-for-sale debt securities	$	99,041	$	98,399