Short-term Investments	3 Months Ended
Mar. 31, 2020
Short Term Investments [Abstract]
Short-term Investments	(3) Short-term Investments The amortized cost and fair value of available-for-sale investments at March 31, 2020 were $109.2 million and $109.9 million, respectively. The amortized cost and fair value of available-for-sale investments at December 31, 2019 were $108.8 million and $108.9 million, respectively. The gross unrecognized holding gains accumulated in other comprehensive loss were not material as of March 31, 2020 and December 31, 2019. As of March 31, 2020 and December 31, 2019, none of the Company’s available-for-sale investments were in unrealized loss positions.

The entire disclosure for investments in certain debt and equity securities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 320
-URI http://asc.fasb.org/subtopic&trid=2209399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-URI http://asc.fasb.org/subtopic&trid=2324412

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-URI http://asc.fasb.org/topic&trid=2196928

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 320
-URI http://asc.fasb.org/subtopic&trid=2176304

Name:	us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration