Loss (Earnings) Per Share - Anti-dilutive Securities (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average securities not included in computation of diluted shares outstanding (in shares)	15,861	11,449	15,856	18,956
Shares issuable upon conversion of PDH Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average securities not included in computation of diluted shares outstanding (in shares)	5,394	0	6,299	8,023
Shares issuable upon conversion of Series A Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average securities not included in computation of diluted shares outstanding (in shares)	2,000	2,000	2,000	2,000
Shares issuable for the contingent consideration
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average securities not included in computation of diluted shares outstanding (in shares)	7,488	9,262	6,655	8,820
Shares issuable upon vesting and exercise of stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average securities not included in computation of diluted shares outstanding (in shares)	56	0	63	0
Shares issuable upon vesting of RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average securities not included in computation of diluted shares outstanding (in shares)	921	186	836	110
Shares issuable under the ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average securities not included in computation of diluted shares outstanding (in shares)	2	1	3	3