Stock Plans - Restricted Stock Units - Vesting (Details) - Restricted Stock Units (RSUs)	12 Months Ended
	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period from the date of grant for restricted stock awards granted	1 year
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period from the date of grant for restricted stock awards granted	1 year
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period from the date of grant for restricted stock awards granted	4 years