Short-term Investments - Summary of Investments in a Continuous Loss Position (Details) $ in Thousands	Mar. 31, 2018 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair value	$ 31,941
Less Than 12 Months, Gross unrealized losses	(111)
12 Months or Greater, Fair value	1,999
12 Months or Greater, Gross unrealized losses	(1)
Total, Fair value	33,940
Total, Gross unrealized losses	112
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair value	23,031
Less Than 12 Months, Gross unrealized losses	(60)
12 Months or Greater, Fair value	0
12 Months or Greater, Gross unrealized losses	0
Total, Fair value	23,031
Total, Gross unrealized losses	60
U.S. government-related debt securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair value	8,910
Less Than 12 Months, Gross unrealized losses	(51)
12 Months or Greater, Fair value	1,999
12 Months or Greater, Gross unrealized losses	(1)
Total, Fair value	10,909
Total, Gross unrealized losses	$ 52