Cash Equivalents and Marketable Securities - Schedule of Estimated Fair Value of Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost	$ 11,521	$ 15,520
Cash equivalents, estimated fair value	11,521	15,520
Marketable securities, amortized cost	36,532	52,645
Marketable securities, gross unrealized gains	13	60
Marketable securities, gross unrealized losses	(147)	(9)
Marketable securities, estimated fair value	36,398	52,696
Money market funds
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost	9,026	7,023
Cash equivalents, estimated fair value	9,026	7,023
Reverse repurchase agreements
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost		6,250
Cash equivalents, estimated fair value		6,250
Commercial paper
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, amortized cost	2,495	2,247
Cash equivalents, estimated fair value	2,495	2,247
Marketable securities, amortized cost	7,725	12,931
Marketable securities, gross unrealized gains	5	15
Marketable securities, estimated fair value	7,730	12,946
Corporate bonds
Schedule Of Available For Sale Securities [Line Items]
Marketable securities, amortized cost	28,807	39,714
Marketable securities, gross unrealized gains	8	45
Marketable securities, gross unrealized losses	(147)	(9)
Marketable securities, estimated fair value	$ 28,668	$ 39,750

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Topic 320
-SubTopic 10
-Section 50
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-Subparagraph (b)
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

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Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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