Share Based Awards - Shares available and options activity (Details) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares Available for Issuance, Beginning Balance	1,301,881
Number of Shares Available for Issuance, Authorized	5,636,269
Shares withheld for net settlement of equity awards (in shares)	815,527
Number of Shares Available for Issuance, Ending Balance	658,843	1,301,881
Options Activity Rollforward
Options outstanding, Beginning Balance	2,898,977
Options exercised	(142,300)
Options cancelled	(83,813)
Options outstanding, Ending Balance	2,672,864	2,898,977
Vested and exercisable- end of the period	2,352,550
Vested and expected to vest - end of the period	2,625,187
Options Activity, Weighted Average Exercise Price Rollforward
Options Outstanding, Weighted-Average Exercise Price, Beginning Balance | $ / shares	$ 5.17
Options Outstanding, Weighted Average Exercise Price Exercised | $ / shares	3.51
Options Outstanding, Weighted Average Exercise Price Cancelled | $ / shares	5.53
Options Outstanding, Weighted-Average Exercise Price, Ending Balance | $ / shares	5.25	$ 5.17
Options Outstanding, Weighted-Average Exercise Price, Vested and exercisable | $ / shares	5.34
Options Outstanding, Weighted-Average Exercise Price, Vested and expected to vest | $ / shares	$ 5.26
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options Outstanding, Weighted-Average Remaining Contractual Term (Years)	4 years 1 month 13 days	4 years 10 months 20 days
Options Outstanding, Weighted-Average Remaining Contractual Term Vested and exercisable (Years)	3 years 9 months 18 days
Options Outstanding, Weighted-Average Remaining Contractual Term Vested and expected to vest (Years)	4 years 29 days
Options Outstanding, Aggregate Intrinsic Value | $	$ 1,424	$ 1,556
Options Outstanding, Vested and exercisable, Aggregate Intrinsic Value | $	1,308
Options Outstanding, Vested and expected to vest, Aggregate Intrinsic Value | $	$ 1,408
Shares under Bonus Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued	(1,730,682)
Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares cancelled or forfeited	83,813
Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued	(5,268,033)
Shares cancelled or forfeited	825,068
Performance Stock Units (PSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued	(1,005,000)