Net Income (Loss) Per Share - Anti-dilutive Securities (Details) - shares	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net Loss Per Share
Anti-dilutive securities (in shares)	11,973,396	14,647,070	12,900,159	14,647,070
Stock options
Net Loss Per Share
Anti-dilutive securities (in shares)	9,654,436	10,192,762	9,654,436	10,192,762
Convertibles notes
Net Loss Per Share
Anti-dilutive securities (in shares)	1,311,031	3,164,557	2,237,794	3,164,557
Restricted stock units
Net Loss Per Share
Anti-dilutive securities (in shares)	1,007,929	1,289,751	1,007,929	1,289,751

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration