Other Long-Term Liabilities (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Other Liabilities, Noncurrent [Abstract]
Contract liabilities, net of current portion	$ 23,489,000	$ 23,880,000
Deferred payments related to acquisitions	5,433,000	5,904,000
Employee separation costs	5,422,000	6,800,000
Deferred rent and other facility costs	1,875,000	6,837,000
Other	1,417,000	1,263,000
Loss on facilities not in use	0	4,332,000
Lease incentives	0	2,300,000
Other long-term liabilities	$ 37,636,000	$ 51,316,000