Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($) Institution	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Patent License Agreements [Abstract]
Threshold period of payment of fees after delivery for fees to be generally presumed not to be fixed or determinable, and for revenue to be deferred and recognized as earned	12 months
Concentration of Credit Risk and Others Risks and Uncertainties [Abstract]
Number of financial institutions holding company's cash | Institution	2
Prepaid Expenses [Abstract]
Prepayment of facility lease for corporate promotional and marketing purposes	$ 4,000
Lease term	10 years
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Adjusted Cost	$ 1,647	$ 8,527	$ 6,627	$ 8,726
Adjusted Cost	2,887		12,445
Unrealized Gains	0		2
Unrealized Losses	(2)		(3)
Fair Value	2,885		12,444
Adjusted Cost	4,314		15,877
Fair Value	4,312		15,876
Investments Available for Sale	2,885		12,444
Cash [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Adjusted Cost	1,427		3,432
Fair Value	1,427		3,432
Cash and Cash Equivalents	1,427		3,432
Mutual Funds [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Adjusted Cost	220		3,195
Unrealized Gains	0		0
Unrealized Losses	0		0
Fair Value	220		3,195
Investments Available for Sale	220		3,195
U.S. Government Securities [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Adjusted Cost			1,254
Unrealized Gains			0
Unrealized Losses			0
Fair Value			1,254
Investments Available for Sale			1,254
U.S. Agency Securities [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Adjusted Cost	2,667		7,996
Unrealized Gains	0		2
Unrealized Losses	(2)		(3)
Fair Value	2,665		7,995
Investments Available for Sale	2,665		7,995
Recurring [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	1,647		6,627
Fair Value	2,665		9,249
Cash and Cash Equivalents	1,647		6,627
Investments Available for Sale	2,665		9,249
Recurring [Member] | Cash [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	1,427		3,432
Cash and Cash Equivalents	1,427		3,432
Recurring [Member] | Level 1 [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	220		3,195
Fair Value	2,665		9,249
Cash and Cash Equivalents	220		3,195
Investments Available for Sale	2,665		9,249
Recurring [Member] | Level 1 [Member] | Mutual Funds [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	220		3,195
Fair Value	0		0
Cash and Cash Equivalents	220		3,195
Investments Available for Sale	0		0
Recurring [Member] | Level 1 [Member] | U.S. Government Securities [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value			0
Fair Value			1,254
Cash and Cash Equivalents			0
Investments Available for Sale			1,254
Recurring [Member] | Level 1 [Member] | U.S. Agency Securities [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	0		0
Fair Value	2,665		7,995
Cash and Cash Equivalents	0		0
Investments Available for Sale	$ 2,665		$ 7,995
August 2013 Contract [Member]
Deferred Revenue [Abstract]
Term of contract	4 years
Contract amount	$ 10,000
Activity under August 2013 contract settlement [Roll Forward]
Deferred Revenue, beginning of period	4,000
Less: Amount amortized as revenue	1,125
Deferred Revenue, end of period	$ 2,875
ASU 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prior period reclassification adjustment		$ 93