Accumulated Other Comprehensive Income (Loss) (Tables)

3 Months Ended

Mar. 31, 2018

Equity [Abstract]

Summary of Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax, from Unrealized Gains (Losses) on Available-for-Sale Marketable Securities

The following table summarizes the changes in accumulated other comprehensive income (loss), or AOCI, net of tax, from unrealized gains (losses) on available-for-sale marketable securities, the Company's only component of AOCI, for the three months ended March 31, 2018 and March 31, 2017.

	Total Accumulated Other Comprehensive Income (Loss)
Balance, December 31, 2017	$	(70	)
Other comprehensive loss before reclassifications		(59	)
Amount reclassified from accumulated other    comprehensive loss		15
Net current period other comprehensive loss		(44	)
Balance, March 31, 2018	$	(114	)
Balance, December 31, 2016	$	3
Other comprehensive income before reclassifications		24
Amount reclassified from accumulated other    comprehensive income		(3	)
Net current period other comprehensive income		21
Balance, March 31, 2017	$	24

Schedule of Reclassification Out of Accumulated Other Comprehensive Income

The reclassifications out of AOCI and into net loss were as follows:

	Three Months Ended March 31,					Affected Line Item in the Statements of
Component of AOCI	2018			2017		Comprehensive Loss
Unrealized gains (losses) on    available-for-sale marketable    securities
Realized gains (losses) on sale of    securities	$	(15	)	$	3	Other income
		—			—	Income tax benefit
	$	(15	)	$	3	Net of tax